Solve 2025 day 7

.gitignore

@@ -4,6 +4,8 @@
 __pycache__/
 *.py[cod]
 *$py.class
+.python-version
+uv.lock
 
 # C extensions
 *.so

2015/d1.py

@@ -1,8 +1,9 @@
-from lib import *
+from lib import get_data
 
-data = open(0).read()
+data = get_data(__file__)
 
-part_2 = True
+t = sum((1 if c == "(" else -1 for c in data))
+print(t)
 
 floor = 0
 for i, c in enumerate(data):
@@ -10,13 +11,6 @@ for i, c in enumerate(data):
         floor += 1
     elif c == ")":
         floor -= 1
-    else:
+    if floor == -1:
-        print(c)
-        assert False
-
-    if part_2 and floor == -1:
         print(i + 1)
         break
-
-if not part_2:
-    print(floor)

2015/d10.py

@@ -1,35 +1,29 @@
-from functools import lru_cache
+from lib import get_data
-data = open(0).read().strip()
 
-part_1 = False
+data = get_data(__file__)
-if part_1:
-    repeats = 40
-else:
-    repeats = 50
 
-@lru_cache
+
-def look_and_say(data: str) -> str:
+def iter(xs):
-    r = ""
+    if not xs:
-    i = 0
+        return []
-    while i < len(data):
+    grouped = []
-        count = 0
+    current_element = xs[0]
-        c = data[i]
+    count = 1
-        while i < len(data) and data[i] == c:
+    for element in xs[1:]:
+        if element == current_element:
             count += 1
-            i += 1
+        else:
-        r += f"{count}{c}"
+            grouped.append(count)
-    return r
+            grouped.append(current_element)
+            current_element = element
+            count = 1
+    grouped.append(count)
+    grouped.append(current_element)
+    return grouped
 
-CHUNK_SIZE = 10000
-for _ in range(repeats):
-    ndata = ""
-    lo, up = 0, CHUNK_SIZE
-    while up < len(data):
-        while up < len(data) and data[up - 1] == data[up]:
-            up += 1
-        ndata += look_and_say(data[lo:up])
-        lo, up = up, up + CHUNK_SIZE
-    ndata += look_and_say(data[lo:up])
-    data = ndata
 
-print(len(data))
+for repeat in [40, 50]:
+    xs = list(map(int, list(data.strip())))
+    for _ in range(repeat):
+        xs = iter(xs)
+    print(len(xs))

2015/d11.py

@@ -1,4 +1,7 @@
-data = open(0).read().strip()
+from lib import get_data
+
+data = get_data(__file__).strip()
+
 
 def is_valid(pw):
     # Passwords must include one increasing straight of at least three letters,
@@ -26,24 +29,26 @@ def is_valid(pw):
         return False
     return True
 
+
 def inc(pw):
     pw = list(map(ord, pw))
     for i in range(len(pw) - 1, -1, -1):
         pw[i] += 1
-        if pw[i] == ord('z') + 1:
+        if pw[i] == ord("z") + 1:
-            pw[i] = ord('a')
+            pw[i] = ord("a")
         else:
             break
     return "".join(map(chr, pw))
 
-part_1 = False
+
+part_1 = True
 valid_count = 0
 while True:
     data = inc(data)
     if is_valid(data):
         valid_count += 1
         if part_1 and valid_count == 1:
-        break
-    elif valid_count == 2:
-        break
             print(data)
+        elif valid_count == 2:
+            print(data)
+            break

2015/d12.py

@@ -1,27 +1,37 @@
+from lib import get_data
 import json
 
-data = open(0).read().strip()
+data = get_data(__file__).strip()
-part_2 = False
 
-def addup(d):
+o = json.loads(data)
-    r = 0
+
-    if isinstance(d, list):
+
-        for e in d:
+def xsum(obj, part_2=False):
-            v = addup(e)
+    t = 0
-            if v is not None:
+    if type(obj) is int:
-                r += v
+        t += obj
-    elif isinstance(d, dict):
+    elif type(obj) is list:
-        for e in d.values():
+        for o in obj:
-            v = addup(e)
+            t += xsum(o, part_2)
-            if v is None:
+    elif type(obj) is dict:
-                return 0
+        if part_2:
-            r += v
+            st = 0
-    elif isinstance(d, str):
+            for o in obj.values():
-        if part_2 and d == "red":
+                st += xsum(o, part_2)
-            return None
+                if type(o) is str and o == "red":
+                    break
             else:
-        r += d
+                t += st
-    return r
+        else:
+            for o in obj.values():
+                t += xsum(o, part_2)
+    elif type(obj) is str:
+        pass
+    else:
+        print(obj)
+        assert False
+    return t
 
-data = json.loads(data)
+
-print(addup(data))
+print(xsum(o))
+print(xsum(o, True))

2015/d13.py

@@ -1,35 +1,32 @@
+from lib import get_data
+from collections import defaultdict
 from itertools import permutations
-data = open(0).read().strip()
 
-part_2 = False
+data = get_data(__file__).strip()
 
+pairs = defaultdict(int)
 people = set()
-scores = {}
+
 for line in data.splitlines():
-    a, _, wl, score, _, _, _, _, _, _, b = line.split()
+    a, _, gainlose, amount, _, _, _, _, _, _, b = line[:-1].split()
-    b = b.replace(".", "")
+    amount = int(amount)
-    score = int(score)
+    if gainlose == "lose":
-    if wl == "lose":
+        amount = -amount
-        score = -score
+    pairs[(a, b)] = amount
     people.add(a)
-    people.add(b)
-    scores[(a, b)] = score
-    if part_2:
-        scores[(a, "me")] = 0
-        scores[("me", a)] = 0
-        scores[(b, "me")] = 0
-        scores[("me", b)] = 0
 
-if part_2:
-    people.add("me")
 
-max_score = 0
+def calc_gain(people):
-for p in permutations(list(people)):
+    maxgain = 0
-    s = 0
+    for xs in permutations(list(people)):
-    for i in range(len(p)):
+        gain = 0
-        a, b = p[i], p[(i + 1) % len(p)]
+        for i in range(len(xs)):
-        s += scores[(a, b)]
+            gain += pairs[(xs[i], xs[(i + 1) % len(xs)])]
-        s += scores[(b, a)]
+            gain += pairs[(xs[(i + 1) % len(xs)], xs[i])]
-    max_score = max(max_score, s)
+        maxgain = max(maxgain, gain)
+    return maxgain
 
-print(max_score)
+
+print(calc_gain(people))
+people.add("Felix")
+print(calc_gain(people))

2015/d14.py

@@ -1,53 +1,40 @@
-import lib
+from lib import get_data
-data = open(0).read().strip()
+from lib import ints, fst
+from collections import defaultdict
 
-part_1 = False
+data = get_data(__file__).strip()
-
+deers = []
-rds = []
-max_dist = 0
-gtime = 2503
-rds = []
 for line in data.splitlines():
-    speed, time, rest = lib.str_to_ints(line)
+    speed, time, rest = ints(line)
-    rds.append([speed, time, rest, 0, 0, 0])
+    deers.append([0, speed, time, rest, time, 0])
-    speed *= 1000
 
-    dist = 0
+points = defaultdict(int)
-    ctime = 0
+for _ in range(2503):
-    while ctime < gtime:
+    max_dists = defaultdict(list)
-        t = min(time, gtime - ctime)
+    for i, deer in enumerate(deers):
-        dist += (speed * t)
+        dist, speed, time, rest, time_left, rest_left = deer
-        ctime += time
+        if time_left > 0:
-        ctime += rest
+            time_left -= 1
-    max_dist = max(dist, max_dist)
+            dist += speed
+        elif time_left == 0:
+            time_left = -1
+            rest_left = rest - 1
+        elif rest_left > 0:
+            rest_left -= 1
+        elif rest_left == 0:
+            time_left = time - 1
+            dist += speed
+            rest_left = -1
+        max_dists[dist].append(i)
 
-if part_1:
+        deer[0] = dist
-    print(max_dist // 1000)
+        deer[4] = time_left
+        deer[5] = rest_left
 
-scores = [0 for _ in range(len(rds))]
+    max_deers = max(max_dists.items())
-for _ in range(gtime):
+    for di in max_deers[1]:
-    for i in range(len(rds)):
+        points[di] += 1
-        speed, time, rest, dist, travel_time, rest_time = rds[i]
-        rd = rds[i]
-        if travel_time < time:
-            rd[3] += speed
-            rd[4] += 1
-        elif rest_time < rest:
-            rd[5] += 1
-            if rd[5] == rest:
-                rd[4] = 0
-                rd[5] = 0
 
-    max_i = -1
-    max_v = 0
-    for i, rd in enumerate(rds):
-        if rd[3] > max_v:
-            max_i = i
-            max_v = rd[3]
-    for i, rd in enumerate(rds):
-        if rd[3] == max_v:
-            scores[i] += 1
-
-if not part_1:
-    print(max(scores))
 
+print(max(map(fst, deers)))
+print(max(points.values()))

2015/d2.py

@@ -1,19 +1,17 @@
-from lib import *
+from lib import get_data, ints
 
-data = open(0).readlines()
+data = get_data(__file__)
 
-part_1 = True
-if part_1:
 a = 0
-    for line in data:
+for line in data.splitlines():
-        l, w, h = list(map(int, line.split("x")))
+    l, w, h = ints(line)
     slack = min([l * w, w * h, h * l])
-        a +=  (2*l*w + 2*w*h + 2*h*l + slack)
+    a += 2 * l * w + 2 * w * h + 2 * h * l + slack
-else: 
+print(a)
+
 a = 0
-    for line in data:
+for line in data.splitlines():
-        l, w, h = list(map(int, line.split("x")))
+    l, w, h = ints(line)
     sd = min([2 * (l + w), 2 * (w + h), 2 * (h + l)])
     a += sd + (l * w * h)
-
 print(a)

2015/d20.py

@@ -4,6 +4,7 @@ import lib
 data = int(open(0).read().strip())
 part_1 = False
 
+
 def calc(n):
     fs = lib.prime_factors(n)
     vs = set([1, n])
@@ -21,6 +22,7 @@ def calc(n):
             r += e * 11
     return r
 
+
 for i in range(3, 10000000):
     c = calc(i)
     if c >= data:

2015/d3.py

@@ -1,9 +1,7 @@
-import sys
+from lib import get_data
-from lib import *
+from lib import V
 
-data = open(0).read()
+data = get_data(__file__)
-
-part_1 = False
 
 DIRS = {
     "^": (-1, 0),
@@ -12,30 +10,27 @@ DIRS = {
     "<": (0, -1),
 }
 
-if part_1:
+pos = V(0, 0)
-    pos = (0, 0)
 poss = set([pos])
 
 for c in data:
     d = DIRS[c]
-        pos = pos[0] + d[0], pos[1] + d[1]
+    pos = pos + d
     poss.add(pos)
 
 print(len(poss))
-    sys.exit(0)
 
-a = (0, 0)
+a = V(0, 0)
-b = (0, 0)
+b = V(0, 0)
 poss = set([a, b])
 for i, c in enumerate(data):
     if i % 2 == 0:
         d = DIRS[c]
-        a = a[0] + d[0], a[1] + d[1]
+        a = a + d
         poss.add(a)
     else:
         d = DIRS[c]
-        b = b[0] + d[0], b[1] + d[1]
+        b = b + d
         poss.add(b)
 
 print(len(poss))
-sys.exit(0)

2015/d4.py

@@ -1,15 +1,9 @@
-from lib import *
+from lib import get_data
 import hashlib
 
-part_1 = True
+data = get_data(__file__).strip()
-
-if part_1:
-    digits = 5
-else:
-    digits = 6
-
-data = open(0).read().strip()
 
+for digits in [5, 6]:
     for i in range(10**9):
         text = data + str(i)
         md5_hash = hashlib.md5(text.encode()).hexdigest()
@@ -19,4 +13,3 @@ for i in range(10**9):
         else:
             print(i)
             break
-

2015/d5.py

@@ -1,53 +1,56 @@
-from lib import *
+from lib import get_data
 
-data = open(0).read()
+data = get_data(__file__)
 
-part_1 = True
+
-if part_1:
+def is_nice(line):
-    res = 0
+    # It contains at least three vowels (aeiou only), like aei, xazegov, or aeiouaeiouaeiou.
-    for line in data.splitlines():
     vc = 0
-        for c in line:
+    for v in "aeiou":
-            if c in "aoeui":
+        vc += line.count(v)
-                vc += 1
     if vc < 3:
-            continue
+        return False
 
-        prev = None
+    # It contains at least one letter that appears twice in a row, like xx,
-        for c in line:
+    # abcdde (dd), or aabbccdd (aa, bb, cc, or dd).
-            if c == prev:
+    for i in range(len(line) - 1):
-                break
+        if line[i] == line[i + 1]:
-            prev = c
-        else:
-            continue
-
-        contains = False
-        ss = ["ab", "cd", "pq", "xy"]
-        for s in ss:
-            if s in line:
-                contains = True
-
-        if contains:
-            continue
-        res += 1
-    print(res)
-else:
-    res = 0
-    for line in data.splitlines():
-        pairs = {}
-        for i in range(0, len(line) - 1):
-            p = line[i:i+2]
-            if p in pairs and i > pairs[p] + 1:
-                break
-            if not p in pairs:
-                pairs[p] = i
-        else:
-            continue
-
-        for i in range(0, len(line) - 2):
-            if line[i] == line[i + 2]:
             break
     else:
-            continue
+        return False
-        res += 1
+
-    print(res)
+    # It does not contain the strings ab, cd, pq, or xy, even if they are
+    # part of one of the other requirements.
+    for i in range(len(line) - 1):
+        cc = "".join(line[i : i + 2])
+        if cc in ["ab", "cd", "pq", "xy"]:
+            return False
+    return True
+
+
+def is_nice_2(line):
+    good = False
+    for i in range(len(line) - 1):
+        cc = "".join(line[i : i + 2])
+        for j in range(i + 2, len(line) - 1):
+            dd = "".join(line[j : j + 2])
+            if cc == dd:
+                good = True
+    if not good:
+        return False
+
+    for i in range(len(line) - 2):
+        cc = "".join(line[i : i + 3])
+        if cc[0] == cc[2]:
+            break
+    else:
+        return False
+    return True
+
+
+t = sum(1 if is_nice(line) else 0 for line in data.splitlines())
+print(t)
+
+
+t = sum(1 if is_nice_2(line) else 0 for line in data.splitlines())
+print(t)

2015/d6.py

@@ -1,33 +1,29 @@
-from lib import *
+from lib import get_data, ints
+from collections import defaultdict as DD
 
-data = open(0).read()
+data = get_data(__file__)
-
-part_2 = True
-lights = [[0 for _ in range(1000)] for _ in range(1000)]
 
+ons = set()
+ons2 = DD(int)
 for line in data.splitlines():
-    x1, y1, x2, y2 = str_to_ints(line)
+    x1, y1, x2, y2 = ints(line)
     for x in range(x1, x2 + 1):
         for y in range(y1, y2 + 1):
-            if part_2:
+            if "off" in line:
-                if "on" in line:
+                if (x, y) in ons:
-                    lights[x][y] += 1
+                    ons.remove((x, y))
-                elif "off" in line:
+                ons2[(x, y)] = max(ons2[(x, y)] - 1, 0)
-                    lights[x][y] = max(0, lights[x][y] - 1)
+            elif "on" in line:
+                ons.add((x, y))
+                ons2[(x, y)] += 1
+            elif "toggle" in line:
+                if (x, y) in ons:
+                    ons.remove((x, y))
                 else:
-                    lights[x][y] += 2
+                    ons.add((x, y))
+                ons2[(x, y)] += 2
             else:
-                if "on" in line:
+                assert False
-                    lights[x][y] = 1
-                elif "off" in line:
-                    lights[x][y] = 0
-                else:
-                    if lights[x][y] == 1:
-                        lights[x][y] = 0
-                    else:
-                        lights[x][y] = 1
 
-res = 0
+print(len(ons))
-for row in lights:
+print(sum(ons2.values()))
-    res += sum(row)
-print(res)

2015/d7.py

@@ -1,90 +1,54 @@
-from lib import *
+from lib import get_data
 
-data = open(0).read()
+data = get_data(__file__)
 
-part_2 = False
+
-if part_2:
+def run(wires={}):
-    gates = {"b": 16076}
+    def get(a):
+        try:
+            return int(a)
+        except ValueError:
+            pass
+        if a in wires:
+            return wires[a]
         else:
-    gates = {}
+            return None
 
-while "a" not in gates:
+    while "a" not in wires:
         for line in data.splitlines():
             lhs, rhs = line.split(" -> ")
-        if part_2 and rhs == "b":
+            if rhs in wires:
                 continue
-        lhs = lhs.strip()
+            match lhs.split():
-        if "NOT" in lhs:
+                case [a, "AND", b]:
-            op, op1 = lhs.split(" ")
+                    a, b = get(a), get(b)
-            assert op == "NOT"
+                    if a is not None and b is not None:
-            try:
+                        wires[rhs] = a & b
-                op1 = int(op1)
+                case [a, "OR", b]:
-                gates[rhs] = ~op1 & 0xffff
+                    a, b = get(a), get(b)
-            except ValueError:
+                    if a is not None and b is not None:
-                if op1 in gates and isinstance(gates[op1], int):
+                        wires[rhs] = a | b
-                    gates[rhs] = ~gates[op1] & 0xffff
+                case [a, "LSHIFT", b]:
-        elif "OR" in lhs:
+                    a, b = get(a), get(b)
-            op1, op, op2 = lhs.split(" ")
+                    if a is not None and b is not None:
-            assert op == "OR"
+                        wires[rhs] = a << b
-            try:
+                case [a, "RSHIFT", b]:
-                op1 = int(op1)
+                    a, b = get(a), get(b)
-            except ValueError:
+                    if a is not None and b is not None:
-                if op1 in gates and isinstance(gates[op1], int):
+                        wires[rhs] = a >> b
-                    op1 = gates[op1]
+                case ["NOT", a]:
-            try:
+                    a = get(a)
-                op2 = int(op2)
+                    if a is not None:
-            except ValueError:
+                        wires[rhs] = ~a & 0xFFFF
-                if op2 in gates and isinstance(gates[op2], int):
+                case [a]:
-                    op2 = gates[op2]
+                    a = get(a)
+                    if a is not None:
+                        wires[rhs] = a
+    return wires
 
-            if not (isinstance(op1, int) and isinstance(op2, int)):
-                continue
-            gates[rhs] = (op1 | op2) 
-        elif "AND" in lhs:
-            op1, op, op2 = lhs.split(" ")
-            assert op == "AND"
-            try:
-                op1 = int(op1)
-            except ValueError:
-                if op1 in gates and isinstance(gates[op1], int):
-                    op1 = gates[op1]
-            try:
-                op2 = int(op2)
-            except ValueError:
-                if op2 in gates and isinstance(gates[op2], int):
-                    op2 = gates[op2]
 
-            if not (isinstance(op1, int) and isinstance(op2, int)):
+a = run()["a"]
-                continue
+print(a)
-            gates[rhs] = (op1 & op2) 
-        elif "LSHIFT" in lhs:
-            op1, op, op2 = lhs.split(" ")
-            op2 = int(op2)
-            try:
-                op1 = int(op1)
-            except ValueError:
-                if op1 in gates:
-                    op1 = gates[op1]
-                else:
-                    continue
-            gates[rhs] = (op1 << op2) & 0xffff
-        elif "RSHIFT" in lhs:
-            op1, op, op2 = lhs.split(" ")
-            op2 = int(op2)
-            try:
-                op1 = int(op1)
-            except ValueError:
-                if op1 in gates:
-                    op1 = gates[op1]
-                else:
-                    continue
-            gates[rhs] = (op1 >> op2) & 0xffff
-        else:
-            try:
-                lhs = int(lhs)
-                gates[rhs] = lhs
-            except ValueError:
-                if lhs in gates:
-                    gates[rhs] = gates[lhs]
 
-print(gates["a"])
+a2 = run(wires={"b": a})["a"]
+print(a2)

2015/d8.py

@@ -1,9 +1,8 @@
-from lib import *
+from lib import get_data
+import re
 
-data = open(0).read()
+data = get_data(__file__)
-part_1 = False
 
-if part_1:
 r1 = re.compile(r"\\x[0-9a-f][0-9a-f]")
 r2 = re.compile(r"\\\\")
 r3 = re.compile(r"\\\"")
@@ -16,11 +15,11 @@ if part_1:
     line = r3.sub("^", line)
     enc += len(line) - 2
 print(mem - enc)
-else:
+
 ori, enc = 0, 0
 for line in data.splitlines():
     ori += len(line)
     line = line.replace("\\", "\\\\")
-        line = line.replace("\"", "\\\"")
+    line = line.replace('"', '\\"')
     enc += len(line) + 2
 print(enc - ori)

2015/d9.py

@@ -1,42 +1,27 @@
-from lib import *
+from lib import get_data
-from typing import Iterator
+from itertools import permutations
 
-# Just for fun instead of using itertools.permutations.
+data = get_data(__file__)
-def permutations(xs) -> Iterator:
-    assert len(xs) > 0
-    if len(xs) == 1:
-        yield xs
-    else:
-        x = xs.pop()
-        for p in permutations(xs):
-            for i in range(len(p) + 1):
-                pn = list(p)
-                pn.insert(i, x)
-                yield pn
-
-part_1 = False
-data = open(0).read()
 
 dists = {}
 nodes = set()
 for line in data.splitlines():
-    path, dist = line.split(" = ")
+    a, _, b, _, d = line.split()
-    dist = int(dist)
-    a, b = path.split(" to ")
     nodes.add(a)
     nodes.add(b)
+    dist = int(d)
     dists[(a, b)] = dist
     dists[(b, a)] = dist
 
-if part_1:
+d_min = 10**12
-    mdist = 10**12
+d_max = 0
-    for route in permutations(nodes):
+for p in permutations(list(nodes)):
-        dist = sum([dists[(route[i], route[i + 1])] for i in range(len(route) - 1)])
+    d = 0
-        mdist = min(dist, mdist)
+    for i in range(len(p) - 1):
-    print(mdist)
+        a, b = p[i], p[i + 1]
-else:
+        d += dists[(a, b)]
-    mdist = 0
+    d_min = min(d, d_min)
-    for route in permutations(nodes):
+    d_max = max(d, d_max)
-        dist = sum([dists[(route[i], route[i + 1])] for i in range(len(route) - 1)])
+
-        mdist = max(dist, mdist)
+print(d_min)
-    print(mdist)
+print(d_max)

2018/d20.py

@@ -1,11 +1,6 @@
 from lib import get_data, add2
 from collections import defaultdict
 
-data = "^WNE$"
-data = "^ENWWW(NEEE|SSE(EE|N))$"
-data = "^ESSWWN(E|NNENN(EESS(WNSE|)SSS|WWWSSSSE(SW|NNNE)))$"
-data = "^WSSEESWWWNW(S|NENNEEEENN(ESSSSW(NWSW|SSEN)|WSWWN(E|WWS(E|SS))))$"
-
 DIRS = {
     "N": (-1, 0),
     "E": (0, 1),
@@ -13,13 +8,19 @@ DIRS = {
     "W": (0, -1),
 }
 
-
+data = get_data(__file__).strip()
-def part_1(data):
 g = defaultdict(set)
-
+seen = set()
 stack: list[tuple[tuple, int, list]] = [((0, 0), 0, [])]
 while len(stack) > 0:
     pos, i, i_outs = stack.pop()
+
+    c = (pos, i, tuple(i_outs))
+    if c in seen:
+        continue
+    else:
+        seen.add(c)
+
     assert i is not None
     while i < len(data):
         c = data[i]
@@ -69,77 +70,18 @@ def part_1(data):
         else:
             assert False
 
-
-    # def parse(i):
-    #     max_len = 0
-    #     cur_len = 0
-    #     while i < len(data):
-    #         c = data[i]
-    #         if c in DIRS.keys():
-    #             i += 1
-    #             cur_len += 1
-    #         elif c == "(":
-    #             sub_len, i = parse(i + 1)
-    #             cur_len += sub_len
-    #         elif c == "|":
-    #             max_len = max(max_len, cur_len)
-    #             cur_len = 0
-    #             i += 1
-    #         elif c == ")":
-    #             all_max = max(max_len, cur_len)
-    #             return all_max, i + 1
-    #         elif c == "$":
-    #             max_len = max(max_len, cur_len)
-    #             i += 1
-    #         else:
-    #             print(c)
-    #             assert False
-    #     return max_len, i
-    #
-    # print(parse(0)[0])
-
-    # g = defaultdict(set)
-    # def parse(xs, i):
-    #     xs_orig = xs.copy()
-    #     xs_done = []
-    #
-    #     while i < len(data):
-    #         c = data[i]
-    #         if c in DIRS.keys():
-    #             for xi in range(len(xs)):
-    #                 pos = xs[xi]
-    #                 npos = add2(pos, DIRS[c])
-    #                 g[pos].add(npos)
-    #                 g[npos].add(pos)
-    #                 xs[xi] = npos
-    #             i += 1
-    #         elif c == "(":
-    #             xs, i = parse(xs, i + 1)
-    #         elif c == "|":
-    #             xs_done += xs
-    #             xs = xs_orig
-    #             i += 1
-    #         elif c == ")":
-    #             xs_done += xs
-    #             return xs_done, i + 1
-    #         elif c == "$":
-    #             xs_done += xs
-    #             i += 1
-    #         else:
-    #             assert False
-    #     return xs_done, i
-    #
-    # parse([(0, 0)], 0)
- 
 seen = set()
 dists = {}
 xs = [(0, 0)]
 steps = 0
+over_thousand = set()
 while len(xs) > 0:
     nxs = []
     for x in xs:
         if x in seen:
             continue
+        if steps >= 1000:
+            over_thousand.add(x)
         seen.add(x)
         dists[x] = steps
         for nb in g[x]:
@@ -149,12 +91,4 @@ def part_1(data):
     steps += 1
 
 print(max(dists.values()))
-
+print(len(over_thousand))
-
-def main():
-    # data = get_data(__file__).strip()
-    part_1(data)
-
-
-if __name__ == "__main__":
-    main()

2018/d24.py

@@ -0,0 +1,179 @@
+import re
+from lib import get_data, ints
+from collections import defaultdict
+from copy import deepcopy
+
+r = re.compile(r"(immune|weak) to ([\w ,]+)")
+r_strength = re.compile(r"(\w+) damage")
+
+data = """Immune System:
+17 units each with 5390 hit points (weak to radiation, bludgeoning) with an attack that does 4507 fire damage at initiative 2
+989 units each with 1274 hit points (immune to fire; weak to bludgeoning, slashing) with an attack that does 25 slashing damage at initiative 3
+
+Infection:
+801 units each with 4706 hit points (weak to radiation) with an attack that does 116 bludgeoning damage at initiative 1
+4485 units each with 2961 hit points (immune to radiation; weak to fire, cold) with an attack that does 12 slashing damage at initiative 4
+ """
+data = get_data(__file__)
+
+ARMY, ID, UNITS, HITS, DAMG, INIT = 0, 1, 2, 3, 4, 5
+
+groups = []
+unit_meta = {}
+
+id = 1
+for a, p in enumerate(data.split("\n\n")):
+    for line in p.splitlines():
+        xs = ints(line)
+        if len(xs) == 0:
+            continue
+        assert len(xs) == 4
+        xs = [a, id] + xs
+
+        (attack,) = r_strength.findall(line)
+        defense = defaultdict(list)
+        for attr, values in r.findall(line):
+            defense[attr] = values.split(", ")
+
+        unit_meta[id] = attack, defense
+        groups.append(xs)
+        id += 1
+
+
+def effective_power(group):
+    return (group[UNITS] * group[DAMG], group[INIT])
+
+
+def damage(g1, g2):
+    """Damage g1 does to g2"""
+    g1_id, g2_id = g1[ID], g2[ID]
+    g1_attack_type = unit_meta[g1_id][0]
+    g2_defenses = unit_meta[g2_id][1]
+    g2_immune = True if g1_attack_type in g2_defenses["immune"] else False
+    g2_weak = True if g1_attack_type in g2_defenses["weak"] else False
+
+    assert (g2_immune and g2_weak) != True
+
+    damage = g1[UNITS] * g1[DAMG]
+    if g2_immune:
+        damage = 0
+    elif g2_weak:
+        damage *= 2
+    return damage
+
+
+groups_orig = deepcopy(groups)
+while True:
+    groups = sorted(groups, key=effective_power, reverse=True)
+    attacks = {}
+    attacked = set()
+    for g in groups:
+        target_max_stats = 0, 0, 0
+        target = None
+        for t in groups:
+            if g[ARMY] == t[ARMY]:
+                continue
+            if g[ID] == t[ID]:
+                continue
+            if t[ID] in attacked:
+                continue
+            target_stats = damage(g, t), effective_power(t)[0], t[INIT]
+            if target_stats[0] == 0:
+                continue
+            if target_stats > target_max_stats:
+                target_max_stats = target_stats
+                target = t
+
+        if target is not None:
+            attacked.add(target[ID])
+            attacks[g[ID]] = target
+
+    groups = sorted(groups, key=lambda g: g[INIT], reverse=True)
+    for g in groups:
+        if g[ID] not in attacks:
+            continue
+        if g[UNITS] <= 0:
+            continue
+
+        target = attacks[g[ID]]
+        cdamage = damage(g, target)
+        units_dead = cdamage // target[HITS]
+        units_dead = units_dead if units_dead <= target[UNITS] else target[UNITS]
+        # print("immune" if g[ARMY] == 0 else "infection", g[ID], "attacks", target[ID], "dead", units_dead)
+        target[UNITS] -= units_dead
+
+    groups = [g for g in groups if g[UNITS] > 0]
+    armies = set()
+    for g in groups:
+        armies.add(g[ARMY])
+    assert len(armies) >= 1
+    if len(armies) == 1:
+        break
+
+
+t = sum(g[UNITS] for g in groups)
+print(t)
+
+
+for boost in range(0, 1800):
+    groups = deepcopy(groups_orig)
+    for g in groups:
+        if g[ARMY] == 0:
+            g[DAMG] += boost
+
+    while True:
+        groups = sorted(groups, key=effective_power, reverse=True)
+        attacks = {}
+        attacked = set()
+        for g in groups:
+            target_max_stats = 0, 0, 0
+            target = None
+            for t in groups:
+                if g[ARMY] == t[ARMY]:
+                    continue
+                if g[ID] == t[ID]:
+                    continue
+                if t[ID] in attacked:
+                    continue
+                target_stats = damage(g, t), effective_power(t)[0], t[INIT]
+                if target_stats[0] == 0:
+                    continue
+                if target_stats > target_max_stats:
+                    target_max_stats = target_stats
+                    target = t
+
+            if target is not None:
+                attacked.add(target[ID])
+                attacks[g[ID]] = target
+
+        groups = sorted(groups, key=lambda g: g[INIT], reverse=True)
+        max_dead = 0
+        for g in groups:
+            if g[ID] not in attacks:
+                continue
+            if g[UNITS] <= 0:
+                continue
+
+            target = attacks[g[ID]]
+            cdamage = damage(g, target)
+            units_dead = cdamage // target[HITS]
+            units_dead = units_dead if units_dead <= target[UNITS] else target[UNITS]
+            max_dead = max(units_dead, max_dead)
+            # print("immune" if g[ARMY] == 0 else "infection", g[ID], "attacks", target[ID], "dead", units_dead)
+            target[UNITS] -= units_dead
+
+        if max_dead == 0:
+            break
+
+        groups = [g for g in groups if g[UNITS] > 0]
+        armies = set()
+        for g in groups:
+            armies.add(g[ARMY])
+        assert len(armies) >= 1
+        if len(armies) == 1:
+            army = groups[0][ARMY]
+            t = sum(g[UNITS] for g in groups)
+            if army == 0:
+                print(t)
+                exit(0)
+            break

2018/d25.py

@@ -0,0 +1,38 @@
+from lib import get_data, ints
+
+
+def mdist(x, y):
+    return sum(abs(a - b) for a, b in zip(x, y))
+
+
+data = get_data(__file__)
+xss = [tuple(ints(line)) for line in data.splitlines()]
+
+# check if we can use set (even though we didn't end up using sets)
+assert len(xss) == len(set(xss))
+
+unplaced = list(xss)
+groups = [[unplaced.pop()]]
+while unplaced:
+    # see if any start fits into the current group
+    current_group = groups[-1]
+    add = None
+    for u in unplaced:
+        for x in current_group:
+            if mdist(u, x) <= 3:
+                add = u
+                break
+        if add is not None:
+            break
+
+    if add is not None:
+        # if yes, add the start to that group and see if another one can be
+        # added to the same group
+        unplaced.remove(add)
+        current_group.append(add)
+    else:
+        # if no, create a new group with an unplaced start
+        groups.append([unplaced.pop()])
+
+
+print(len(groups))

2019/d22.py

@@ -4,16 +4,17 @@ from math import gcd
 data = get_data(__file__)
 deck = list(range(10007))
 
+# part 1
 for line in data.splitlines():
     if "new stack" in line:
         deck = list(reversed(deck))
     elif "cut" in line:
-        n, = str_to_ints(line)
+        (n,) = str_to_ints(line)
         deck = deck[n:] + deck[:n]
     elif "increment" in line:
         new_deck = [-1] * len(deck)
         pos = 0
-        n, = str_to_ints(line)
+        (n,) = str_to_ints(line)
         deck = list(reversed(deck))
         while deck:
             new_deck[pos] = deck.pop()
@@ -24,30 +25,94 @@ for line in data.splitlines():
 
 print(deck.index(2019))
 
-# idea: just follow the index of the target card
-len = 119315717514047
 len = 10007
-index = 2019
+orig_index = 2019
 
-
+# figure out how to reverse...
-for i in range(101741582076661):
+index = orig_index
 for line in data.splitlines():
     if "new stack" in line:
-            index = len - (index + 1)
+        new_index = len - (index + 1)
+        rev_index = -(new_index - len + 1)
+        assert rev_index == index
+        index = new_index
     elif "cut" in line:
-            cut, = str_to_ints(line)
+        (cut,) = str_to_ints(line)
         cut = (len + cut) % len
         if index >= cut:
-                index = index - cut
+            new_index = index - cut
         else:
-                index = (len - cut) + index
+            new_index = (len - cut) + index
+        rev_index = (new_index + cut) % len
+        assert rev_index == index
+        index = new_index
+        # calculate index from new_index and store in rev_index
     elif "increment" in line:
-            n, = str_to_ints(line)
+        (n,) = str_to_ints(line)
         assert gcd(n, len) == 1
         new_index = (n * index) % len
         m = mod_inverse(n, len)
-            assert (new_index * m) % len == index
+        rev_index = (new_index * m) % len
+        assert rev_index == index
         index = new_index
-    break
 
-print(index)
+assert index == deck.index(2019)
+
+# check that reverse approach works
+for line in reversed(data.splitlines()):
+    if "new stack" in line:
+        index = -(index - len + 1)
+    elif "cut" in line:
+        (cut,) = str_to_ints(line)
+        cut = (len + cut) % len
+        index = (index + cut) % len
+    elif "increment" in line:
+        (n,) = str_to_ints(line)
+        assert gcd(n, len) == 1
+        m = mod_inverse(n, len)
+        index = (index * m) % len
+assert index == orig_index
+
+lines = list(reversed(data.splitlines()))
+
+# new length of deck
+len = 119315717514047
+
+# get expression for one loop using sympy
+from sympy import symbols, simplify
+
+index = symbols("index")
+expr = index
+for line in lines:
+    if "new stack" in line:
+        # index = -(index - len + 1)
+        expr = -(expr - len + 1)
+    elif "cut" in line:
+        (cut,) = str_to_ints(line)
+        cut = (len + cut) % len
+        # index = (index + cut) % len
+        expr = expr + cut
+    elif "increment" in line:
+        (n,) = str_to_ints(line)
+        assert gcd(n, len) == 1
+        m = mod_inverse(n, len)
+        # index = (index * m) % len
+        expr = expr * m
+
+# we can see that expression is in the form (a - b * i) % m
+expr = simplify(expr % len)
+coeff_dict = expr.args[0].as_coefficients_dict()
+a = coeff_dict[1]
+b = -coeff_dict[index]
+
+# math
+n_shuffles = 101741582076661
+r0 = 2020
+m = len
+p = (-b) % m
+p_t = pow(p, n_shuffles, m)
+inv_b1 = mod_inverse(b + 1, m)
+term1 = (p_t * r0) % m
+term2 = (a * (1 - p_t) * inv_b1) % m
+r_t = (term1 + term2) % m
+print(r_t)

2019/d23.py

@@ -0,0 +1,47 @@
+from lib import get_data, str_to_ints
+from d9 import Amp
+
+xs = str_to_ints(get_data(__file__))
+first_255 = True
+nat = None
+y_prev = None
+
+amps = []
+for i in range(50):
+    a = Amp(xs)
+    a.feed(i)
+    a.go()
+    amps.append(a)
+
+for j in range(1_000_000):
+    was_active = False
+    for i, a in enumerate(amps):
+        a.go()
+        if a.input_required:
+            a.feed(-1)
+
+        if len(a.outputs) > 0:
+            was_active = True
+            while len(a.outputs) < 3:
+                a.go()
+            addr = a.pop()
+            x = a.pop()
+            y = a.pop()
+            if addr == 255:
+                nat = (x, y)
+                if first_255:
+                    print(y)
+                    first_255 = False
+            else:
+                amps[addr].feed(x)
+                amps[addr].feed(y)
+
+    if not was_active and nat is not None:
+        x, y = nat
+        if y == y_prev:
+            print(y)
+            exit()
+        amps[0].feed(x)
+        amps[0].feed(y)
+        nat = None
+        y_prev = y

2019/d24.py

@@ -0,0 +1,107 @@
+from lib import get_data, Grid2D, add2
+from collections import defaultdict
+
+
+data = get_data(__file__)
+
+g = Grid2D(data)
+seen = set()
+while True:
+    h = g.hash()
+    if h in seen:
+        break
+    else:
+        seen.add(h)
+
+    gn = g.clone_with_val(".")
+    for r in range(g.n_rows):
+        for c in range(g.n_cols):
+            p = (r, c)
+            nb_bugs = sum(1 for nb in g.neighbors_ort(p) if g[nb] == "#")
+            if g[p] == "#" and nb_bugs == 1:
+                gn[p] = "#"
+            if g[p] == "." and nb_bugs in [1, 2]:
+                gn[p] = "#"
+    g = gn
+
+
+t = 0
+p = 1
+for r in range(g.n_rows):
+    for c in range(g.n_cols):
+        if g[(r, c)] == "#":
+            t += p
+        p *= 2
+print(t)
+
+N = (-1, 0)
+E = (0, 1)
+S = (1, 0)
+W = (0, -1)
+DIRS = [N, E, S, W]
+ROW, COL = 0, 1
+
+# data = get_data(__file__)
+g = Grid2D(data)
+bugs = [(0, r, c) for (r, c) in g.find("#")]
+middle = (g.n_rows // 2, g.n_cols // 2)
+rows, cols = g.n_rows, g.n_cols
+
+
+def get_edge(side):
+    edges = {
+        S: [(0, c) for c in range(cols)],
+        N: [(rows - 1, c) for c in range(cols)],
+        W: [(r, cols - 1) for r in range(rows)],
+        E: [(r, 0) for r in range(rows)],
+    }
+    return edges[side]
+
+
+def get_neighbors(pos):
+    level, row, col = pos
+    neighbors = []
+
+    for d in DIRS:
+        nb = add2((row, col), d)
+        if nb == middle:
+            for ir, ic in get_edge(d):
+                neighbors.append((level - 1, ir, ic))
+        elif nb[ROW] in {-1, rows} or nb[COL] in {-1, cols}:
+            nr, nc = nb
+            if nr == -1:
+                neighbors.append((level + 1, *add2(middle, N)))
+            if nr == rows:
+                neighbors.append((level + 1, *add2(middle, S)))
+            if nc == -1:
+                neighbors.append((level + 1, *add2(middle, W)))
+            if nc == cols:
+                neighbors.append((level + 1, *add2(middle, E)))
+        else:
+            nr, nc = nb
+            neighbors.append((level, nr, nc))
+    return neighbors
+
+
+assert len(get_neighbors((0, 1, 1))) == 4
+assert len(get_neighbors((0, 3, 3))) == 4
+assert len(get_neighbors((0, 0, 3))) == 4
+assert len(get_neighbors((0, 0, 4))) == 4
+assert len(get_neighbors((0, 2, 3))) == 8
+
+for _ in range(200):
+    neighbors = defaultdict(int)
+    current_bugs = set(bugs)
+    for pos in bugs:
+        for nb in get_neighbors(pos):
+            neighbors[nb] += 1
+
+    new_bugs = []
+    for pos, count in neighbors.items():
+        if pos in current_bugs and count == 1:
+            new_bugs.append(pos)
+        if pos not in current_bugs and count in [1, 2]:
+            new_bugs.append(pos)
+    bugs = new_bugs
+
+print(len(bugs))

2019/d25.py

@@ -0,0 +1,160 @@
+from lib import get_data, ints
+from d9 import Amp
+from itertools import combinations
+
+data = get_data(__file__)
+xs = ints(data)
+
+commands = [
+    "north",
+    "take candy cane",
+    "west",
+    "south",
+    "south",
+    "take fuel cell",
+    "south",
+    "take manifold",
+    "north",
+    "north",
+    "west",
+    "take mutex",
+    "north",
+    "south",
+    "south",
+    "south",
+    "take coin",
+    "south",
+    "north",
+    "east",
+    "take cake",
+    "west",
+    "east",
+    "north",
+    "south",
+    "west",
+    "east",
+    "east",
+    "north",
+    "south",
+    "west",
+    "north",
+    "west",
+    "east",
+    "west",
+    "south",
+    "west",
+    "north",
+    "north",
+    "south",
+    "west",
+    "north",
+    "east",
+    "south",
+    "west",
+    "east",
+    "west",
+    "south",
+    "west",
+    "take dehydrated water",
+    "west",
+    "east",
+    "west",
+    "south",
+    "take prime number",
+    "south",
+    "north",
+    "east",
+    "east",
+    "west",
+    "north",
+    "east",
+    "east",
+    "north",
+    "south",
+    "west",
+    "north",
+    "west",
+    "south",
+    "inv",
+    "west",
+]
+
+items = [
+    "cake",
+    "prime number",
+    "mutex",
+    "dehydrated water",
+    "coin",
+    "manifold",
+    "candy cane",
+    "fuel cell",
+]
+
+
+def run_command(a, s):
+    for c in s:
+        a.feed(ord(c))
+    a.feed(10)
+    a.go()
+
+
+a = Amp(xs)
+for c in commands:
+    a.go()
+    while a.outputs:
+        a.go()
+        a.pop()
+        # print(chr(a.pop()), end="")
+    run_command(a, c)
+    a.go()
+
+
+def try_all(a):
+    subsets = [list(combinations(items, r)) for r in range(1, len(items) + 1)]
+    subsets = [item for sublist in subsets for item in sublist]
+    for subset in subsets:
+        for item in items:
+            c = f"drop {item}"
+            run_command(a, c)
+            a.go()
+            while a.outputs:
+                a.pop()
+                a.go()
+
+        for item in subset:
+            c = f"take {item}"
+            run_command(a, c)
+            a.go()
+            while a.outputs:
+                a.pop()
+                a.go()
+
+        run_command(a, "west")
+
+        output_str = ""
+        while a.outputs:
+            a.go()
+            output_str += chr(a.pop())
+        if "lighter" in output_str:
+            pass
+        elif "heavier" in output_str:
+            pass
+        else:
+            (password,) = ints(output_str)
+            print(password)
+            exit()
+
+
+while True:
+    a.go()
+
+    output_str = ""
+    while a.outputs:
+        a.go()
+        output_str += chr(a.pop())
+
+    try_all(a)
+
+    if a.input_required:
+        c = input(">")
+        run_command(a, c)

2021/d1.py

@@ -0,0 +1,20 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__)
+xs = ints(data)
+
+t = 0
+for a, b in zip(xs, xs[1:]):
+    if b > a:
+        t += 1
+print(t)
+
+t = 0
+prev_sum = 10**12
+for i in range(len(xs) - 2):
+    s = sum(xs[i : i + 3])
+    if s > prev_sum:
+        t += 1
+    prev_sum = s
+print(t)

2021/d10.py

@@ -0,0 +1,63 @@
+from lib import get_data
+
+data = get_data(__file__).strip()
+
+OPEN = "([{<"
+CLOSE = ")]}>"
+
+
+def part1(line):
+    score = {
+        ")": 3,
+        "]": 57,
+        "}": 1197,
+        ">": 25137,
+    }
+    stack = []
+    for c in line:
+        if c in OPEN:
+            stack.append(OPEN.index(c))
+        elif c in CLOSE:
+            ci = CLOSE.index(c)
+            if stack and stack[-1] == ci:
+                stack.pop()
+                continue
+            else:
+                return score[c]
+        else:
+            assert False
+    return 0
+
+
+def part2(line):
+    stack = []
+    for c in line:
+        if c in OPEN:
+            stack.append(OPEN.index(c))
+        elif c in CLOSE:
+            ci = CLOSE.index(c)
+            if stack and stack[-1] == ci:
+                stack.pop()
+                continue
+            else:
+                assert False
+        else:
+            assert False
+    score = 0
+    for v in reversed(stack):
+        score *= 5
+        score += v + 1
+    return score
+
+
+s1 = 0
+s2s = []
+for line in data.splitlines():
+    s = part1(line)
+    if s == 0:
+        s2s.append(part2(line))
+    s1 += s
+
+print(s1)
+s2 = sorted(s2s)[len(s2s) // 2]
+print(s2)

2021/d11.py

@@ -0,0 +1,37 @@
+from lib import get_data
+from lib import Grid2D
+
+data = get_data(__file__).strip()
+g = Grid2D(data)
+
+flashes_100 = 0
+all_flash_round = None
+for i in range(10**9):
+    for row in range(g.n_rows):
+        for col in range(g.n_cols):
+            g[(row, col)] = str(int(g[(row, col)]) + 1)
+
+    has_flashed = set()
+    more_flashes = True
+    while more_flashes:
+        more_flashes = False
+        for row in range(g.n_rows):
+            for col in range(g.n_cols):
+                level = int(g[(row, col)])
+                if level > 9 and (row, col) not in has_flashed:
+                    more_flashes = True
+                    for nb in g.neighbors_adj((row, col)):
+                        g[nb] = str(int(g[nb]) + 1)
+                    has_flashed.add((row, col))
+    for oct in has_flashed:
+        g[oct] = "0"
+
+    if i < 100:
+        flashes_100 += len(has_flashed)
+
+    if len(has_flashed) == g.n_rows * g.n_cols:
+        all_flash_round = i + 1
+        break
+
+print(flashes_100)
+print(all_flash_round)

2021/d12.py

@@ -0,0 +1,56 @@
+from lib import get_data
+from lib import Grid2D
+from lib import ints
+from collections import deque
+from collections import defaultdict
+
+data = get_data(__file__).strip()
+g = defaultdict(list)
+
+
+for line in data.splitlines():
+    a, b = line.strip().split("-")
+    g[a].append(b)
+    g[b].append(a)
+
+
+def no_doubles(path):
+    path = [p for p in path if p.islower()]
+    return len(path) == len(set(path))
+
+
+for part in [1, 2]:
+    start = ("start", ())
+    visited = set()
+    queue = deque([start])
+
+    total = 0
+    while queue:
+        vertex = queue.popleft()
+        if vertex in visited:
+            continue
+        visited.add(vertex)
+
+        current, path = vertex
+
+        neighbors = []
+        for neighbor in g[current]:
+            if neighbor == "end":
+                total += 1
+            elif neighbor == "start":
+                continue
+            elif neighbor.islower():
+                if neighbor not in path or (part == 2 and no_doubles(path)):
+                    new_path = tuple(list(path) + [neighbor])
+                    nb = (neighbor, new_path)
+                    if nb not in visited:
+                        queue.append(nb)
+            elif neighbor.isupper():
+                new_path = tuple(list(path) + [neighbor])
+                nb = (neighbor, new_path)
+                if nb not in visited:
+                    queue.append(nb)
+            else:
+                assert False
+
+    print(total)

2021/d13.py

@@ -0,0 +1,51 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__).strip()
+
+
+def print_from_xy(xs):
+    x_min = min(v[0] for v in xs)
+    x_max = max(v[0] for v in xs)
+    y_min = min(v[1] for v in xs)
+    y_max = max(v[1] for v in xs)
+    for y in range(y_min, y_max + 1):
+        row = ""
+        for x in range(x_min, x_max + 1):
+            if (x, y) in xs:
+                row += "#"
+            else:
+                row += " "
+        print(row)
+
+
+p1, p2 = data.split("\n\n")
+xs = set([tuple(ints(line)) for line in p1.splitlines()])
+
+folds = []
+for line in p2.splitlines():
+    d = "x" if "x=" in line else "y"
+    (n,) = ints(line)
+    folds.append((d, n))
+
+
+first = None
+for d, n in folds:
+    if d == "x":
+        to_move = [(x, y) for (x, y) in xs if x > n]
+        for x, y in to_move:
+            xs.remove((x, y))
+            new_x = n - (x - n)
+            xs.add((new_x, y))
+    elif d == "y":
+        to_move = [(x, y) for (x, y) in xs if y > n]
+        for x, y in to_move:
+            xs.remove((x, y))
+            new_y = n - (y - n)
+            xs.add((x, new_y))
+    else:
+        assert False
+    first = first or len(xs)
+
+print(first)
+print_from_xy(xs)

2021/d14.py

@@ -0,0 +1,43 @@
+from lib import get_data
+from itertools import pairwise
+from collections import defaultdict
+
+data = get_data(__file__)
+orig_t, p2 = data.split("\n\n")
+
+pairs = {}
+for line in p2.splitlines():
+    ls, rs = line.split(" -> ")
+    assert ls not in pairs
+    pairs[ls] = rs
+
+for steps in [10, 40]:
+    t = str(orig_t)
+    start_letter = t[0]
+    end_letter = t[-1]
+    td = defaultdict(int)
+    for a, b in pairwise(t):
+        td[a + b] += 1
+
+    for _ in range(steps):
+        ntd = defaultdict(int)
+        for pair, count in td.items():
+            if pair in pairs:
+                a, b = pair
+                c = pairs[pair]
+                ntd[a + c] += count
+                ntd[c + b] += count
+            else:
+                ntd[pair] += count
+        td = ntd
+
+    counts = defaultdict(int)
+    for (a, b), count in td.items():
+        counts[a] += count
+        counts[b] += count
+    counts = {k: v // 2 for k, v in counts.items()}
+    counts[start_letter] += 1
+    counts[end_letter] += 1
+
+    r = max(counts.values()) - min(counts.values())
+    print(r)

2021/d15.py

@@ -0,0 +1,83 @@
+from lib import get_data
+from lib import Grid2D
+import heapq
+
+data = get_data(__file__)
+
+
+def new_data(data, repeat=5):
+    new_lines = []
+    for line in data.splitlines():
+        new_line = str(line)
+        for i in range(len(line) * repeat):
+            ni = i - len(line)
+            if ni < 0:
+                continue
+            nc = int(new_line[ni]) + 1
+            if nc == 10:
+                nc = 1
+            new_line += str(nc)
+        new_lines.append(new_line)
+
+    for i in range(len(data.splitlines()) * repeat):
+        ni = i - len(data.splitlines())
+        if ni < 0:
+            continue
+        line = list(new_lines[ni])
+        for i in range(len(line)):
+            nc = int(line[i]) + 1
+            if nc == 10:
+                nc = 1
+            line[i] = str(nc)
+        line = "".join(line)
+        new_lines.append(line)
+
+    data = "\n".join(new_lines)
+    return data
+
+
+big_data = new_data(data)
+
+for data in [data, big_data]:
+    g = Grid2D(data)
+
+    def dist(n1, n2):
+        """cost from node to node"""
+        if n1 == 0:
+            return 0
+        return int(g[n2])
+
+    def h(node):
+        """heuristic function (never overestimate)"""
+        return abs(g.n_rows - 1 - node[0]) + abs(g.n_cols - 1 - node[1])
+
+    def is_goal(node):
+        return node == (g.n_rows - 1, g.n_cols - 1)
+
+    def neighbors(node):
+        return list(g.neighbors_ort(node))
+
+    starts = [(0, 0)]
+    open_set = []
+    g_score = {}
+    cost = None
+
+    for start in starts:
+        heapq.heappush(open_set, (h(start), start))
+        g_score[start] = dist(0, start)
+
+    while open_set:
+        current_f_score, current = heapq.heappop(open_set)
+        if is_goal(current):
+            assert current_f_score == g_score[current]
+            cost = g_score[current]
+            break
+
+        for neighbor in neighbors(current):
+            tentative_g_score = g_score[current] + dist(current, neighbor)
+            if neighbor not in g_score or tentative_g_score < g_score[neighbor]:
+                g_score[neighbor] = tentative_g_score
+                f_score = g_score[neighbor] + h(neighbor)
+                heapq.heappush(open_set, (f_score, neighbor))
+
+    print(cost)

2021/d16.py

@@ -0,0 +1,85 @@
+from lib import get_data
+
+
+data = get_data(__file__)
+
+bs = ""
+for c in data.strip():
+    b = bin(int(c, 16))[2:]
+    b = "0" * (4 - len(b)) + b
+    bs += b
+
+total_v = 0
+
+
+def parse(bs: str, i: int):
+    v = int(bs[i : i + 3], 2)
+    global total_v
+    total_v += v
+    i += 3
+    t = int(bs[i : i + 3], 2)
+    i += 3
+
+    # print(v, t)
+    if t == 4:
+        lv = ""
+        while True:
+            seg = bs[i : i + 5]
+            lv += seg[1:]
+            i += 5
+            if seg[0] == "0":
+                break
+        lv = int(lv, 2)
+        return i, lv
+
+    vs = []
+    if bs[i] == "0":
+        # total length of bits
+        i += 1
+        bits = int(bs[i : i + 15], 2)
+        i += 15
+        i_max = i + bits
+        while True:
+            i, v = parse(bs, i)
+            vs.append(v)
+            if i >= i_max:
+                break
+    elif bs[i] == "1":
+        # number of sub-packets
+        i += 1
+        num_sub = int(bs[i : i + 11], 2)
+        i += 11
+        vs = []
+        for _ in range(num_sub):
+            i, v = parse(bs, i)
+            vs.append(v)
+    else:
+        assert False
+
+    if t == 0:
+        return i, sum(vs)
+    elif t == 1:
+        x = 1
+        for v in vs:
+            x *= v
+        return i, x
+    elif t == 2:
+        return i, min(vs)
+    elif t == 3:
+        return i, max(vs)
+    elif t == 5:
+        assert len(vs) == 2
+        return i, 1 if vs[0] > vs[1] else 0
+    elif t == 6:
+        assert len(vs) == 2
+        return i, 1 if vs[0] < vs[1] else 0
+    elif t == 7:
+        assert len(vs) == 2
+        return i, 1 if vs[0] == vs[1] else 0
+    else:
+        assert False
+
+
+p2 = parse(bs, 0)[1]
+print(total_v)
+print(p2)

2021/d17.py

@@ -0,0 +1,35 @@
+from lib import get_data
+from lib import ints
+
+
+data = get_data(__file__)
+x_min, x_max, y_min, y_max = ints(data)
+
+
+def simulate(x, y, vx, vy):
+    height_max = 0
+    while x <= x_max and y >= y_min:
+        height_max = max(y, height_max)
+        if x_min <= x <= x_max and y_min <= y <= y_max:
+            return True, height_max
+
+        x += vx
+        y += vy
+        if vx != 0:
+            vx = vx - 1 if vx > 0 else vx + 1
+        vy -= 1
+    return False, 0
+
+
+height_max = 0
+total = set()
+for vx in range(1, 2000):
+    for vy in range(-2000, 2000):
+        in_target, height = simulate(0, 0, vx, vy)
+        if in_target:
+            total.add((vx, vy))
+        if in_target and height > height_max:
+            height_max = height
+
+print(height_max)
+print(len(total))

2021/d18.py

@@ -0,0 +1,115 @@
+from lib import get_data
+from math import ceil, floor
+from itertools import combinations
+
+data = """[[[0,[5,8]],[[1,7],[9,6]]],[[4,[1,2]],[[1,4],2]]]
+[[[5,[2,8]],4],[5,[[9,9],0]]]
+[6,[[[6,2],[5,6]],[[7,6],[4,7]]]]
+[[[6,[0,7]],[0,9]],[4,[9,[9,0]]]]
+[[[7,[6,4]],[3,[1,3]]],[[[5,5],1],9]]
+[[6,[[7,3],[3,2]]],[[[3,8],[5,7]],4]]
+[[[[5,4],[7,7]],8],[[8,3],8]]
+[[9,3],[[9,9],[6,[4,9]]]]
+[[2,[[7,7],7]],[[5,8],[[9,3],[0,2]]]]
+[[[[5,2],5],[8,[3,7]]],[[5,[7,5]],[4,4]]]"""
+data = get_data(__file__)
+
+
+def parse(line):
+    xs = list(line)
+    for i in range(len(xs)):
+        try:
+            xs[i] = int(xs[i])
+        except ValueError:
+            pass
+    assert line == "".join(map(str, xs))
+    return xs
+
+
+def reduce(xs):
+    reduced, nesting = False, 0
+    for i in range(len(xs)):
+        c = xs[i]
+        if c == "[" and nesting == 4 and not reduced:
+            lhs, rhs = xs[i + 1], xs[i + 3]
+            if not (type(lhs) is int and type(rhs) is int):
+                continue
+            xs = xs[:i] + [0] + xs[i + 5 :]
+
+            for j in range(i - 1, -1, -1):
+                if type(xs[j]) is int:
+                    xs[j] += lhs
+                    break
+
+            for j in range(i + 1, len(xs)):
+                if type(xs[j]) is int:
+                    xs[j] += rhs
+                    break
+            reduced = True
+            break
+        elif c == "[":
+            nesting += 1
+        elif c == "]":
+            nesting -= 1
+
+    if not reduced:
+        for i in range(len(xs)):
+            c = xs[i]
+            if type(c) is int and c >= 10:
+                p = [floor(c / 2), ceil(c / 2)]
+                xs = xs[:i] + ["[", p[0], ",", p[1], "]"] + xs[i + 1 :]
+                reduced = True
+                break
+    return xs
+
+
+def restore(xs):
+    return "".join(map(str, xs))
+
+
+assert restore(reduce(parse("[[[[[9,8],1],2],3],4]"))) == "[[[[0,9],2],3],4]"
+assert restore(reduce(parse("[7,[6,[5,[4,[3,2]]]]]"))) == "[7,[6,[5,[7,0]]]]"
+assert (
+    restore(reduce(parse("[[3,[2,[1,[7,3]]]],[6,[5,[4,[3,2]]]]]")))
+    == "[[3,[2,[8,0]]],[9,[5,[4,[3,2]]]]]"
+)
+assert (
+    restore(reduce(parse("[[3,[2,[8,0]]],[9,[5,[4,[3,2]]]]]")))
+    == "[[3,[2,[8,0]]],[9,[5,[7,0]]]]"
+)
+
+
+def add(a, b):
+    s = ["["] + a + [","] + b + ["]"]
+    while True:
+        ns = reduce(s)
+        if s == ns:
+            break
+        s = ns
+    return s
+
+
+a = "[[[[4,3],4],4],[7,[[8,4],9]]]"
+b = "[1,1]"
+assert restore(add(parse(a), parse(b))) == "[[[[0,7],4],[[7,8],[6,0]]],[8,1]]"
+
+lines = list(data.splitlines())
+s = parse(lines[0].strip())
+for line in lines[1:]:
+    s = add(s, parse(line.strip()))
+
+
+def get_mag(xs):
+    if type(xs) is int:
+        return xs
+    return get_mag(xs[0]) * 3 + get_mag(xs[1]) * 2
+
+
+print(get_mag(eval(restore(s))))
+
+lines = list(data.splitlines())
+m = 0
+for a, b in combinations(lines, 2):
+    m = max(m, get_mag(eval(restore(add(parse(a), parse(b))))))
+    m = max(m, get_mag(eval(restore(add(parse(b), parse(a))))))
+print(m)

2021/d19.py

@@ -0,0 +1,121 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+from itertools import permutations, product
+
+V3 = tuple[int, int, int]
+
+data = get_data(__file__)
+scanners = []
+for block in data.split("\n\n"):
+    scanner = []
+    for line in block.splitlines()[1:]:
+        a, b, c = ints(line)
+        scanner.append((a, b, c))
+    scanners.append(scanner)
+
+
+def rotate(vi: V3) -> list[V3]:
+    r = []
+    for p in permutations(vi):
+        for f in product([1, -1], repeat=3):
+            v = tuple([a * b for a, b in zip(p, f)])
+            r.append(v)
+    return r
+
+
+assert len(rotate((8, 0, 7))) == 48
+
+
+def sub(a: V3, b: V3) -> V3:
+    return a[0] - b[0], a[1] - b[1], a[2] - b[2]
+
+
+def add(a: V3, b: V3) -> V3:
+    return a[0] + b[0], a[1] + b[1], a[2] + b[2]
+
+
+def relative(scanner: list[V3]):
+    d = defaultdict(list)
+    for i in range(len(scanner)):
+        for j in range(i + 1, len(scanner)):
+            for ii, jj in [(i, j), (j, i)]:
+                a, b = scanner[ii], scanner[jj]
+                delta = sub(a, b)
+                d[delta].append((a, b))
+    return d
+
+
+def overlap(scanner_1, scanner_2):
+    expected_overlaps = 15
+    r1 = relative(scanner_1)
+    scanners_2 = []
+    for scanner in list(zip(*list(map(rotate, scanner_2)))):
+        os = set()
+        r2 = relative(scanner)
+        # number of bacon pairs that have the same offset
+        t = sum(1 for k1 in r1.keys() if k1 in r2)
+        if t >= expected_overlaps:
+            for k1, v1 in r1.items():
+                if k1 in r2:
+                    ((abs1, abs2),) = v1
+                    ((rel1, rel2),) = r2[k1]
+                    os.add(sub(abs1, rel1))
+                    os.add(sub(abs2, rel2))
+            if len(os) == 1:
+                # found the right orientation for scanner_2
+                scanners_2.append((os.pop(), scanner))
+            else:
+                r2 = None
+        else:
+            r2 = None
+
+    if len(scanners_2) == 0:
+        return None
+    ((orig_2, scanner_2_rel),) = scanners_2
+    scanner_2_abs = [add(orig_2, b) for b in scanner_2_rel]
+    return orig_2, scanner_2_abs
+
+
+origs = [(0, 0, 0)]
+todo = set(range(len(scanners)))
+done = set([0]) if 0 in todo else set([todo.pop()])
+todo.discard(0)
+while todo:
+    for i in range(len(scanners)):
+        for j in range(len(scanners)):
+            if i == j:
+                continue
+            if i not in done:
+                continue
+            if j in done:
+                continue
+            r = overlap(scanners[i], scanners[j])
+
+            if r is None:
+                continue
+            o, s2 = r
+            origs.append(o)
+            no = len(set(scanners[i]).intersection(s2))
+            if no >= 12:
+                scanners[j] = s2
+                done.add(j)
+                todo.discard(j)
+                # print(f"{i} < {no} > {j} at {o}")
+
+
+all = []
+for s in scanners:
+    all += s
+print(len(set(all)))
+
+
+def mdist(a, b):
+    return sum(abs(aa - bb) for aa, bb in zip(a, b))
+
+
+m = 0
+for i in range(len(origs)):
+    for j in range(i + 1, len(origs)):
+        m = max(m, mdist(origs[i], origs[j]))
+print(m)

2021/d2.py

@@ -0,0 +1,24 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__)
+
+aim, h2, d2 = 0, 0, 0
+h, d = 0, 0
+for line in data.splitlines():
+    (v,) = ints(line)
+    if "forward" in line:
+        h2 += v
+        d2 += aim * v
+        h += v
+    elif "down" in line:
+        aim += v
+        d += v
+    elif "up" in line:
+        aim -= v
+        d -= v
+    else:
+        assert False
+
+print(h * d)
+print(h2 * d2)

2021/d20.py

@@ -0,0 +1,51 @@
+from lib import get_data
+
+data = get_data(__file__)
+
+for rounds in [2, 50]:
+    algo, img = data.strip().split("\n\n")
+    algo = algo.replace("\n", "")
+
+    xs = set()
+    img = img.splitlines()
+    for row in range(len(img)):
+        for col in range(len(img[0])):
+            if img[row][col] == "#":
+                xs.add((row, col))
+
+    for i in range(rounds):
+        y_min = min(v[0] for v in xs) - 6
+        y_max = max(v[0] for v in xs) + 6
+        x_min = min(v[1] for v in xs) - 6
+        x_max = max(v[1] for v in xs) + 6
+
+        nxs = set()
+        for row in range(y_min, y_max + 1):
+            for col in range(x_min, x_max + 1):
+                bin = ""
+                for ro in range(3):
+                    for co in range(3):
+                        if (row + ro, col + co) in xs:
+                            bin += "1"
+                        else:
+                            bin += "0"
+                bin = int(bin, 2)
+                if algo[bin] == "#":
+                    nxs.add((row, col))
+
+        xs = nxs
+        y_min_trim = y_min + 7
+        y_max_trim = y_max - 8
+        x_min_trim = x_min + 7
+        x_max_trim = x_max - 8
+
+        # special clean-up required because input creates pixels when there
+        # are no other pixels around (0b0_0000_0000)
+        if i % 2 == 1:
+            xs = [
+                (r, c)
+                for (r, c) in xs
+                if y_min_trim <= r <= y_max_trim and x_min_trim <= c <= x_max_trim
+            ]
+
+    print(len(xs))

2021/d21.py

@@ -0,0 +1,65 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+
+
+FIELD = 10
+DICE = 100
+dice = -1
+
+data = get_data(__file__)
+
+_, p1, _, p2 = ints(data)
+pos = [p1 - 1, p2 - 1]
+scores = [0, 0]
+
+dice_rolls = 0
+not_done = True
+while not_done:
+    for p in range(len(scores)):
+        dice_rolls += 3
+        for _ in range(3):
+            dice += 1 % DICE
+            pos[p] = (pos[p] + (dice + 1)) % FIELD
+        scores[p] += pos[p] + 1
+        if scores[p] >= 1000:
+            not_done = False
+            break
+
+r = min(scores) * dice_rolls
+print(r)
+
+_, p1, _, p2 = ints(data)
+pos = (p1 - 1, p2 - 1)
+scores = (0, 0)
+unis = defaultdict(int)
+won = [0, 0]
+unis[(0, pos, scores)] += 1
+
+while unis:
+    nunis = defaultdict(int)
+    for (turn, opos, scores), count in unis.items():
+        other = (turn + 1) % 2
+        poss = [opos[turn]]
+        for _ in range(3):
+            nposs = []
+            for dice in range(1, 3 + 1):
+                for pos in poss:
+                    npos = (pos + dice) % FIELD
+                    nposs.append(npos)
+            poss = nposs
+
+        for npos_player in poss:
+            score = scores[turn] + npos_player + 1
+            if score >= 21:
+                won[turn] += count
+            else:
+                nscores = list(scores)
+                nscores[turn] = score
+                npos = list(opos)
+                npos[turn] = npos_player
+                state = (other, tuple(npos), tuple(nscores))
+                nunis[state] += count
+    unis = nunis
+
+print(max(won))

2021/d22.py

@@ -0,0 +1,92 @@
+from lib import get_data
+from lib import ints
+from dataclasses import dataclass
+from typing import Optional
+
+data = get_data(__file__)
+
+limit = 50
+ps = set()
+for i, line in enumerate(data.splitlines()):
+    x_min, x_max, y_min, y_max, z_min, z_max = ints(line)
+    for x in range(max(x_min, -limit), min(x_max, limit) + 1):
+        for y in range(max(y_min, -limit), min(y_max, limit) + 1):
+            for z in range(max(z_min, -limit), min(z_max, limit) + 1):
+                if line.startswith("on"):
+                    ps.add((x, y, z))
+                elif line.startswith("off"):
+                    if (x, y, z) in ps:
+                        ps.remove((x, y, z))
+                else:
+                    assert False
+
+print(len(ps))
+
+
+@dataclass
+class Line:
+    a: int
+    b: int
+
+    def intersects(self, other: "Line") -> bool:
+        return self.b > other.a and self.a < other.b
+
+    def intersection(self, other: "Line") -> Optional["Line"]:
+        if not self.intersects(other):
+            return None
+        return Line(max(self.a, other.a), min(self.b, other.b))
+
+    def length(self) -> int:
+        assert self.b > self.a
+        return self.b - self.a + 1
+
+
+@dataclass(frozen=True)
+class Cube:
+    on: bool
+    x: Line
+    y: Line
+    z: Line
+
+    @classmethod
+    def from_line(cls, line: str) -> "Cube":
+        xs = ints(line)
+        assert len(xs) == 6
+        lines = [Line(*xs[i:i+2]) for i in range(0, len(xs), 2)]
+        on = True if line.startswith("on") else False
+        return Cube(on, *lines)
+
+    def volume(self) -> int:
+        return (self.x.length() * self.y.length() * self.z.length()) * (1 if self.on else -1)
+
+    def intersects(self, other: "Cube") -> bool:
+        return (
+            self.x.intersects(other.x)
+            and self.y.intersects(other.y)
+            and self.z.intersects(other.z)
+        )
+
+    def intersection(self, other: "Cube") -> Optional["Cube"]:
+        x = self.x.intersection(other.x)
+        y = self.y.intersection(other.y)
+        z = self.z.intersection(other.z)
+        if x is None or y is None or z is None:
+            return None
+        return Cube(not self.on, x, y, z)
+
+
+# Inclusion/exclusion principle from set theory
+cubes = []
+for line in data.splitlines():
+    cc = Cube.from_line(line)
+    ncubes = []
+    for i in range(len(cubes)):
+        c = cubes[i]
+        ic = c.intersection(cc)
+        if ic is not None:
+            cubes.append(ic)
+
+    if cc.on:
+        cubes.append(cc)
+
+print(sum(c.volume() for c in cubes))

2021/d23.py

@@ -0,0 +1,143 @@
+import heapq
+from lib import get_data
+from lib import Grid2D
+from collections import deque
+from collections import defaultdict
+
+CHAR_COSTS = {"A": 1, "B": 10, "C": 100, "D": 1000}
+HALL_SPOTS = set([(1, x) for x in [1, 2, 4, 6, 8, 10, 11]])
+
+for n_amphs in [2, 4]:
+    AMPH_SPOTS = {}
+    for i, c in enumerate("ABCD"):
+        spots = [(r, 3 + i * 2) for r in range(2, 2 + n_amphs)]
+        AMPH_SPOTS[c] = tuple(spots)
+
+    data = get_data(__file__)
+    lines = data.splitlines()
+    if n_amphs == 4:
+        lines.insert(-2, "  #D#C#B#A#  ")
+        lines.insert(-2, "  #D#B#A#C#  ")
+    lines[-2] = lines[-2] + "  "
+    lines[-1] = lines[-1] + "  "
+    data = "\n".join(lines)
+
+    g = Grid2D(data)
+    GRID_EMPTY = g.clone()
+
+    def mdist(p1, p2):
+        return abs(p1[0] - p2[0]) + abs(p1[1] - p2[1])
+
+    poss = []
+    for c in "ABCD":
+        for coord in g.find(c):
+            poss.append((coord[0], coord[1], c, False))
+            GRID_EMPTY[coord] = "."
+    poss = tuple(poss)
+
+    def dist(n1, n2):
+        """cost from node to node"""
+        if n1 == 0:
+            return 0
+        return n2[1] - n1[1]
+
+    def h(node):
+        """heuristic function (never overestimate)"""
+        cost = 0
+        for r, c, char, _ in node[0]:
+            if (r, c) not in AMPH_SPOTS[char]:
+                cost += mdist((r, c), AMPH_SPOTS[char][0]) * CHAR_COSTS[char]
+        return cost
+
+    def is_goal(node):
+        for r, c, char, _ in node[0]:
+            if (r, c) in AMPH_SPOTS[char]:
+                continue
+            return False
+        return True
+
+    def find_accessible_spots(pos: tuple[int, int], char, blocked):
+        start = (pos, 0)
+        visited = set()
+        queue = deque([start])
+        cost = CHAR_COSTS[char]
+
+        options = []
+        while queue:
+            pos, dist = queue.popleft()
+            if pos in visited:
+                continue
+            visited.add(pos)
+
+            for neighbor in GRID_EMPTY.neighbors_ort(pos):
+                if neighbor in blocked:
+                    continue
+                if GRID_EMPTY[neighbor] != ".":
+                    continue
+                if neighbor not in visited:
+                    new_state = (neighbor, dist + cost)
+                    queue.append(new_state)
+                    options.append(new_state)
+        return options
+
+    def neighbors(node):
+        nbs = []
+
+        blocked = []
+        blocked_to_char = defaultdict(str)
+        for r, c, char, _ in node[0]:
+            blocked.append((r, c))
+            blocked_to_char[(r, c)] = char
+
+        for i, (r, c, char, moved) in enumerate(node[0]):
+            if moved and (r, c) in AMPH_SPOTS[char]:
+                continue
+
+            for pos, dist in find_accessible_spots((r, c), char, blocked):
+                # cannot move to hall spots twice
+                if pos in HALL_SPOTS and moved:
+                    continue
+
+                # can only move to hall spot or amph spot (of the right type)
+                if not (pos in HALL_SPOTS or pos in AMPH_SPOTS[char]):
+                    continue
+
+                # only move into amph spot if all lower spots are already occupied by the correct amph
+                if pos in AMPH_SPOTS[char] and not all(
+                    blocked_to_char[AMPH_SPOTS[char][i]] == char
+                    for i in range(
+                        AMPH_SPOTS[char].index(pos) + 1, len(AMPH_SPOTS[char])
+                    )
+                ):
+                    continue
+
+                amphs = list(node[0])
+                amphs[i] = (pos[0], pos[1], char, True)
+                neighbor = (tuple(amphs), node[1] + dist)
+                nbs.append(neighbor)
+        return nbs
+
+    starts = [(poss, 0)]
+    open_set = []
+    g_score = {}
+    cost = None
+
+    for start in starts:
+        heapq.heappush(open_set, (h(start), start))
+        g_score[start] = dist(0, start)
+
+    while open_set:
+        current_f_score, current = heapq.heappop(open_set)
+        if is_goal(current):
+            assert current_f_score == g_score[current]
+            cost = g_score[current]
+            break
+
+        for neighbor in neighbors(current):
+            tentative_g_score = g_score[current] + dist(current, neighbor)
+            if neighbor not in g_score or tentative_g_score < g_score[neighbor]:
+                g_score[neighbor] = tentative_g_score
+                f_score = g_score[neighbor] + h(neighbor)
+                heapq.heappush(open_set, (f_score, neighbor))
+
+    print(cost)

2021/d24.py

@@ -0,0 +1,45 @@
+from lib import get_data
+
+data = get_data(__file__)
+
+
+def run(number):
+    inputs = list(map(int, str(number)))
+    assert len(inputs) == 14
+
+    w, x, z = 0, 0, 0
+    i = 0
+    for i in range(len(inputs)):
+        w = inputs[i]
+        # print(f"{w=:3} {x=:3}                       {z=}")
+
+        to_add_x = [15, 15, 12, 13, -12, 10, -9, 14, 13, -14, -11, -2, -16, -14][i]
+        to_div_z = [1, 1, 1, 1, 26, 1, 26, 1, 1, 26, 26, 26, 26, 26][i]
+        to_add_z = [15, 10, 2, 16, 12, 11, 5, 16, 6, 15, 3, 12, 10, 13][i]
+
+        zz = z
+        x = (z % 26) + to_add_x
+        z = z // to_div_z
+
+        # print(f"{zz % 26=} + {to_add_x=} {x=}")
+
+        if x == w:
+            # print(f"added                     = 0")
+            pass
+        else:
+            z *= 26
+            z += w + to_add_z
+            # print(f"added {w=} + {to_add_z=} = {w + to_add_z}")
+        # print()
+
+    # print(f"\nEND:\n{w=} {x=} {z=}", "\n" * 15)
+    return z
+
+
+largest_model_nr = 89959794919939
+assert run(largest_model_nr) == 0
+print(largest_model_nr)
+
+lowest_model_nr = 17115131916112
+assert run(lowest_model_nr) == 0
+print(lowest_model_nr)

2021/d25.py

@@ -0,0 +1,29 @@
+from lib import get_data
+from lib import Grid2D
+
+data = get_data(__file__)
+
+g = Grid2D(data)
+seen = set()
+for i in range(10**9):
+    if g.hash() in seen:
+        print(i)
+        break
+
+    seen.add(g.hash())
+    blocked = set(g.find(">v"))
+    for p in g.find(">"):
+        np = (p[0], (p[1] + 1) % g.n_cols)
+        if np in blocked:
+            continue
+        g[p] = "."
+        g[np] = ">"
+
+    blocked = set(g.find(">v"))
+    for p in g.find("v"):
+        np = ((p[0] + 1) % g.n_rows , p[1])
+        if np in blocked:
+            continue
+        g[p] = "."
+        g[np] = "v"
+

2021/d3.py

@@ -0,0 +1,56 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+
+data = get_data(__file__)
+
+
+def count_one_zero(xs, index):
+    ones, zeros = 0, 0
+    for x in xs:
+        if x[index] == "1":
+            ones += 1
+        elif x[index] == "0":
+            zeros += 1
+        else:
+            assert False
+    return (ones, zeros)
+
+
+a = ""
+b = ""
+lines = list(data.strip().splitlines())
+for i in range(len(lines[0])):
+    ones, zeros = count_one_zero(lines, i)
+    if ones > zeros:
+        a += "1"
+        b += "0"
+    elif zeros > ones:
+        a += "0"
+        b += "1"
+    else:
+        assert False
+a, b = int(a, 2), int(b, 2)
+print(a * b)
+
+lines = list(data.strip().splitlines())
+for i in range(len(lines[0])):
+    ones, zeros = count_one_zero(lines, i)
+    c = "1" if ones >= zeros else "0"
+    lines = [l for l in lines if l[i] == c]
+    if len(lines) == 1:
+        break
+(line,) = lines
+a = int(line, 2)
+
+lines = list(data.strip().splitlines())
+for i in range(len(lines[0])):
+    ones, zeros = count_one_zero(lines, i)
+    c = "0" if zeros <= ones else "1"
+    lines = [l for l in lines if l[i] == c]
+    if len(lines) == 1:
+        break
+
+(line,) = lines
+b = int(line, 2)
+print(a * b)

2021/d4.py

@@ -0,0 +1,52 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__).strip()
+
+boards = []
+numbers = None
+for i, p in enumerate(data.split("\n\n")):
+    if i == 0:
+        numbers = ints(p)
+    else:
+        board = []
+        for line in p.splitlines():
+            board.append(ints(line))
+        boards.append(board)
+
+assert numbers is not None
+first_won = None
+last_won = None
+boards_done = list()
+for n in numbers:
+    for i in range(len(boards)):
+        if i in boards_done:
+            continue
+        board = boards[i]
+        board = [[f if n != f else None for f in row] for row in board]
+        boards[i] = board
+        for row in board:
+            if all(cell is None for cell in row):
+                if not i in boards_done:
+                    boards_done.append(i)
+        for col in zip(*board):
+            if all(cell is None for cell in col):
+                if not i in boards_done:
+                    boards_done.append(i)
+
+        if len(boards_done) > 0 and first_won is None:
+            first_won = (i, n)
+
+        if len(boards_done) == len(boards):
+            last_won = (i, n)
+            break
+    if len(boards_done) == len(boards):
+        break
+
+assert first_won is not None
+assert last_won is not None
+
+for i, n in [first_won, last_won]:
+    board = boards[i]
+    a = sum([sum([n if n is not None else 0 for n in row]) for row in board])
+    print(a * n)

2021/d5.py

@@ -0,0 +1,39 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+
+data = get_data(__file__).strip()
+
+counts = defaultdict(int)
+for line in data.splitlines():
+    x1, y1, x2, y2 = ints(line)
+    if x1 == x2 or y1 == y2:
+        if x1 == x2:
+            for y in range(min(y1, y2), max(y1, y2) + 1):
+                counts[(x1, y)] += 1
+        elif y1 == y2:
+            for x in range(min(x1, x2), max(x1, x2) + 1):
+                counts[(x, y1)] += 1
+        else:
+            assert False
+
+r = sum(1 for v in counts.values() if v > 1)
+print(r)
+
+
+for line in data.splitlines():
+    x1, y1, x2, y2 = ints(line)
+    if x1 == x2 or y1 == y2:
+        pass
+    else:
+        dx = 1 if x2 > x1 else -1
+        dy = 1 if y2 > y1 else -1
+
+        while (x1, y1) != (x2, y2):
+            counts[(x1, y1)] += 1
+            x1 += dx
+            y1 += dy
+        counts[(x2, y2)] += 1
+
+r = sum(1 for v in counts.values() if v > 1)
+print(r)

2021/d6.py

@@ -0,0 +1,32 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+
+data = get_data(__file__).strip()
+xs = ints(data)
+
+for _ in range(80):
+    for i in range(len(xs)):
+        if xs[i] == 0:
+            xs[i] = 6
+            xs.append(8)
+        else:
+            xs[i] -= 1
+
+print(len(xs))
+
+xs = ints(data)
+fish = defaultdict(int)
+for x in xs:
+    fish[x] += 1
+
+for _ in range(256):
+    new_fish = defaultdict(int)
+    new_fish[8] = fish[0]
+    new_fish[6] = fish[0]
+    for i in range(1, 9):
+        new_fish[i - 1] += fish[i]
+    fish = new_fish
+
+r = sum(fish.values())
+print(r)

2021/d7.py

@@ -0,0 +1,20 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__).strip()
+xs = ints(data)
+
+
+def d(t, x):
+    n = abs(t - x)
+    return n * (n + 1) // 2
+
+
+s_min_1 = 10**16
+s_min_2 = 10**16
+for t in range(min(xs), max(xs) + 1):
+    s_min_1 = min(s_min_1, sum(abs(t - x) for x in xs))
+    s_min_2 = min(s_min_2, sum(d(t, x) for x in xs))
+
+print(s_min_1)
+print(s_min_2)

2021/d8.py

@@ -0,0 +1,65 @@
+from lib import get_data
+from itertools import permutations
+
+data = get_data(__file__).strip()
+
+code_to_num = {
+    "cf": 1,
+    "acf": 7,
+    "bcdf": 4,
+    "acdeg": 2,
+    "acdfg": 3,
+    "abdfg": 5,
+    "abcefg": 0,
+    "abdefg": 6,
+    "abcdfg": 9,
+    "abcdefg": 8,
+}
+
+
+def translate(inn, mapping):
+    out = ""
+    for c in inn:
+        out += mapping[c]
+    return "".join(sorted(out))
+
+
+def decode(inn, out):
+    s = "abcdefg"
+    m = None
+    for p in permutations(s):
+        m = {k: v for k, v in zip(p, s)}
+        all = set(code_to_num.keys())
+        for in_code in inn:
+            out_code = translate(in_code, m)
+            if out_code in all:
+                all.remove(out_code)
+
+        if len(all) == 0:
+            break
+        else:
+            m = None
+
+    assert m is not None
+
+    o = 0
+    d = 1000
+    for out_code in out:
+        out_code = translate(out_code, m)
+        v = code_to_num[out_code]
+        o += d * v
+        d //= 10
+    return o
+
+
+s1 = 0
+s2 = 0
+for line in data.splitlines():
+    inn, out = line.strip().split(" | ")
+    inn = inn.split()
+    out = out.split()
+    s1 += sum(1 for v in out if len(v) in [2, 3, 4, 7])
+    s2 += decode(inn, out)
+
+print(s1)
+print(s2)

2021/d9.py

@@ -0,0 +1,47 @@
+from lib import get_data, Grid2D
+from collections import deque
+
+data = get_data(__file__).strip()
+g = Grid2D(data)
+
+s = 0
+low_points = []
+for row in range(g.n_rows):
+    for col in range(g.n_cols):
+        h = int(g[(row, col)])
+        for nb in g.neighbors_ort((row, col)):
+            if int(g[nb]) <= h:
+                break
+        else:
+            low_points.append((row, col))
+            s += 1 + h
+
+print(s)
+
+basins = []
+for row, col in low_points:
+    start = None
+    visited = set()
+    queue = deque([(row, col)])
+
+    while queue:
+        vertex = queue.popleft()
+        if vertex in visited:
+            continue
+        visited.add(vertex)
+
+        neighbors = []
+        for neighbor in g.neighbors_ort(vertex):
+            if neighbor in visited:
+                continue
+
+            neighbor_height = int(g[neighbor])
+            if neighbor_height < 9:
+                queue.append(neighbor)
+
+    basins.append(len(visited))
+
+s = 1
+for x in sorted(basins)[-3:]:
+    s *= x
+print(s)

2021/lib.py

@@ -0,0 +1 @@
+../lib.py

2024/d01.py

@@ -0,0 +1,21 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__)
+
+s = 0
+ass, bss = [], []
+s2 = 0
+
+# I had an intuition for this and then went for loops...
+xs, ys = list(zip(*[ints(line) for line in data.splitlines()]))
+
+xs = sorted(xs)
+ys = sorted(ys)
+
+for a, b in zip(xs, ys):
+    s += max(a, b) - min(a, b)
+    s2 += ys.count(a) * a
+
+print(s)
+print(s2)

2024/d02.py

@@ -0,0 +1,42 @@
+from lib import get_data
+from lib import ints
+
+
+data = get_data(__file__)
+
+s1 = 0
+s2 = 0
+
+for line in data.splitlines():
+    xs = ints(line)
+
+    deltas = []
+    for i in range(len(xs) - 1):
+        deltas.append(xs[i + 1] - xs[i])
+        if abs(xs[i + 1] - xs[i]) not in [1, 2, 3]:
+            break
+    else:
+        if deltas[0] < 0 and all(deltas[i] < 0 for i in range(len(deltas))):
+            s1 += 1
+        elif deltas[0] > 0 and all(deltas[i] > 0 for i in range(len(deltas))):
+            s1 += 1
+
+    sublists = [xs[:i] + xs[i + 1 :] for i in range(len(xs))]
+    found = False
+    for xs in sublists:
+        deltas = []
+        for i in range(len(xs) - 1):
+            deltas.append(xs[i + 1] - xs[i])
+            if abs(xs[i + 1] - xs[i]) not in [1, 2, 3]:
+                break
+        else:
+            if deltas[0] < 0 and all(deltas[i] < 0 for i in range(len(deltas))):
+
+                found = True
+            if deltas[0] > 0 and all(deltas[i] > 0 for i in range(len(deltas))):
+                found = True
+    if found:
+        s2 += 1
+
+print(s1)
+print(s2)

2024/d03.py

@@ -0,0 +1,24 @@
+import re
+from lib import get_data
+from lib import ints
+
+
+data = get_data(__file__)
+
+t1 = 0
+t2 = 0
+enabled = True
+r = re.compile(r"mul\(\d+,\d+\)|do\(\)|don't\(\)")
+for m in r.findall(data):
+    if m == "do()":
+        enabled = True
+    elif m == "don't()":
+        enabled = False
+    else:
+        a, b = ints(m)
+        t1 += a * b
+        if enabled:
+            t2 += a * b
+
+print(t1)
+print(t2)

2024/d04.py

@@ -0,0 +1,44 @@
+from lib import get_data
+from lib import Grid2D
+
+data = get_data(__file__)
+g = Grid2D(data)
+
+DIRS = {
+    "N": (-1, 0),
+    "E": (0, 1),
+    "S": (1, 0),
+    "W": (0, -1),
+    "NE": (-1, 1),
+    "SE": (1, 1),
+    "SW": (1, -1),
+    "NW": (-1, -1),
+}
+
+t1, t2 = 0, 0
+for row in range(g.n_rows):
+    for col in range(g.n_cols):
+        for d in DIRS.values():
+            coords = [(row + d[0] * i, col + d[1] * i) for i in range(len("XMAS"))]
+            for (r, c), z in zip(coords, "XMAS"):
+                if not (0 <= r < g.n_rows and 0 <= c < g.n_cols and g[(r, c)] == z):
+                    break
+            else:
+                t1 += 1
+
+        coords = [
+            (row - 1, col - 1),
+            (row - 1, col + 1),
+            (row, col),
+            (row + 1, col - 1),
+            (row + 1, col + 1),
+        ]
+        for s in ["MMASS", "MSAMS", "SSAMM", "SMASM"]:
+            for (r, c), z in zip(coords, s):
+                if not (0 <= r < g.n_rows and 0 <= c < g.n_cols and g[(r, c)] == z):
+                    break
+            else:
+                t2 += 1
+
+print(t1)
+print(t2)

2024/d05.py

@@ -0,0 +1,37 @@
+from lib import get_data
+from lib import ints
+
+
+def fix(xs):
+    change = True
+    while change:
+        change = False
+        for rule in rules.splitlines():
+            x, y = ints(rule)
+            if not (x in xs and y in xs):
+                continue
+            i, j = xs.index(x), xs.index(y)
+            if not i < j:
+                xs[i], xs[j] = xs[j], xs[i]
+                change = True
+    return xs
+
+
+rules, pages = get_data(__file__).split("\n\n")
+
+t1, t2 = 0, 0
+for page in pages.splitlines():
+    xs = ints(page)
+    for rule in rules.splitlines():
+        x, y = ints(rule)
+        if not (x in xs and y in xs):
+            continue
+        if not (xs.index(x) < xs.index(y)):
+            xs = fix(ints(page))
+            t2 += xs[len(xs) // 2]
+            break
+    else:
+        t1 += xs[len(xs) // 2]
+
+print(t1)
+print(t2)

2024/d06.py

@@ -0,0 +1,51 @@
+from lib import get_data
+from lib import Grid2D
+
+data = get_data(__file__)
+
+
+DIRS = [
+    (-1, 0),
+    (0, 1),
+    (1, 0),
+    (0, -1),
+]
+
+g = Grid2D(data)
+
+t = 0
+for rr in range(g.n_rows):
+    for cc in range(g.n_cols):
+        (p,), dir = g.find("^"), 0
+        seen = set()
+        loop = False
+
+        if g[(rr, cc)] == "#":
+            continue
+
+        if g[(rr, cc)] != "^":
+            g[(rr, cc)] = "#"
+
+        while True:
+            if (p, dir) in seen:
+                loop = True
+                break
+            seen.add((p, dir))
+            r, c = p[0] + DIRS[dir][0], p[1] + DIRS[dir][1]
+            if not (0 <= r < g.n_rows and 0 <= c < g.n_cols):
+                break
+
+            if g[(r, c)] == "#":
+                dir = (dir + 1) % 4
+            else:
+                p = (r, c)
+
+        if g[(rr, cc)] == "^":
+            print(len(set(pos for pos, _ in seen)))
+        else:
+            g[(rr, cc)] = "."
+
+        if loop:
+            t += 1
+
+print(t)

2024/d07.py

@@ -0,0 +1,30 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__)
+
+
+def combs(acc, rest, part_2=False):
+    if rest == []:
+        return acc
+
+    nacc = []
+    for a in acc:
+        nacc.append(a + rest[0])
+        nacc.append(a * rest[0])
+        if part_2:
+            nacc.append(int(str(a) + str(rest[0])))
+    return combs(nacc, rest[1:], part_2)
+
+
+t1, t2 = 0, 0
+for line in data.splitlines():
+    xs = ints(line)
+    expected = xs[0]
+    if xs[0] in combs([xs[1]], xs[2:]):
+        t1 += xs[0]
+    if xs[0] in combs([xs[1]], xs[2:], True):
+        t2 += xs[0]
+
+print(t1)
+print(t2)

2024/d08.py

@@ -0,0 +1,34 @@
+from lib import get_data
+from lib import Grid2D
+from itertools import combinations
+from collections import defaultdict
+
+data = get_data(__file__)
+g = Grid2D(data)
+
+d = defaultdict(list)
+
+for row in range(g.n_rows):
+    for col in range(g.n_cols):
+        p = (row, col)
+        if g[p] != ".":
+            d[g[p]].append((row, col))
+
+aa = set()
+bb = set()
+for coords in d.values():
+    for c, d in combinations(coords, 2):
+        bb.add(c)
+        bb.add(d)
+        for a, b in [(c, d), (d, c)]:
+            d = b[0] - a[0], b[1] - a[1]
+            a = b[0] + d[0], b[1] + d[1]
+            if g.contains(a):
+                aa.add(a)
+            a = b[0] + d[0], b[1] + d[1]
+            while g.contains(a):
+                bb.add(a)
+                a = a[0] + d[0], a[1] + d[1]
+
+print(len(aa))
+print(len(bb))

2024/d09.py

@@ -0,0 +1,102 @@
+from lib import get_data
+from copy import deepcopy
+
+data = get_data(__file__)
+i = 0
+f = True
+d = []
+spaces = 0
+for c in data.strip():
+    if f:
+        d.append([int(c), i, f])
+        f = False
+        i += 1
+    else:
+        spaces += int(c)
+        d.append([int(c), -1, f])
+        f = True
+
+d2 = deepcopy(d)
+
+BLOCKS, ID, FULL = 0, 1, 2
+empty_i = 1
+full_i = len(d) - 1
+assert d[full_i][FULL]
+
+while empty_i < full_i:
+    empty = d[empty_i]
+    full = d[full_i]
+
+    if empty[BLOCKS] == full[BLOCKS]:
+        empty[ID] = full[ID]
+        empty[FULL] = True
+        full[BLOCKS] = 0
+        full[FULL] = False
+    elif empty[BLOCKS] < full[BLOCKS]:
+        empty[ID] = full[ID]
+        empty[FULL] = True
+        full[BLOCKS] -= empty[BLOCKS]
+    elif empty[BLOCKS] > full[BLOCKS]:
+        new = [empty[BLOCKS] - full[BLOCKS], empty[ID], False]
+        empty[ID] = full[ID]
+        empty[BLOCKS] = full[BLOCKS]
+        empty[FULL] = True
+        d.insert(empty_i + 1, new)
+        full_i += 1
+        full[BLOCKS] = 0
+        full[FULL] = False
+    else:
+        assert False
+
+    while d[empty_i][FULL] == True:
+        empty_i += 1
+
+    while d[full_i][FULL] == False:
+        full_i -= 1
+
+t = 0
+i = 0
+for b in d:
+    if b[FULL] == False:
+        break
+    for _ in range(b[BLOCKS]):
+        t += i * b[ID]
+        i += 1
+print(t)
+
+d = d2
+
+full_i = len(d) - 1
+while full_i > 0:
+    full = d[full_i]
+    prev_i = full_i
+    for empty_i in range(0, full_i):
+        empty = d[empty_i]
+        if full[FULL] == False:
+            continue
+        if empty[FULL]:
+            continue
+        if empty[BLOCKS] < full[BLOCKS]:
+            continue
+
+        if empty[BLOCKS] == full[BLOCKS]:
+            empty[FULL] = True
+            empty[ID] = full[ID]
+            full[FULL] = False
+        elif empty[BLOCKS] > full[BLOCKS]:
+            full[FULL] = False
+            new = [full[BLOCKS], full[ID], True]
+            d[empty_i] = new
+            d.insert(empty_i + 1, [empty[BLOCKS] - full[BLOCKS], -1, False])
+            full_i += 1
+        break
+    full_i -= 1
+
+t = 0
+i = 0
+for b in d:
+    for _ in range(b[BLOCKS]):
+        if b[FULL] == True:
+            t += i * b[ID]
+        i += 1
+print(t)

2024/d09_2.py

@@ -0,0 +1,81 @@
+from lib import get_data
+
+data = get_data("d9.py")
+
+
+def parse(data):
+    xs = []
+    f = True
+    i = 0
+    for c in data.strip():
+        if f:
+            for _ in range(int(c)):
+                xs.append(i)
+            f = False
+            i += 1
+        else:
+            for _ in range(int(c)):
+                xs.append(".")
+            f = True
+    return xs
+
+
+def score(xs):
+    t = 0
+    for i, j in enumerate(xs):
+        if j == ".":
+            continue
+        t += i * j
+    return t
+
+
+xs = parse(data)
+i, j = 0, len(xs) - 1
+while i <= j:
+    while xs[i] != ".":
+        i += 1
+
+    while xs[j] == ".":
+        j -= 1
+
+    if not i <= j:
+        break
+
+    xs[i], xs[j] = xs[j], xs[i]
+
+print(score(xs))
+xs = parse(data)
+
+idx = {}
+ids = []
+for i, x in enumerate(xs):
+    if x == ".":
+        continue
+    if not x in idx:
+        idx[x] = i
+        ids.append(x)
+
+while ids:
+    id = ids.pop()
+    i1, i2 = idx[id], idx[id]
+    while i2 < len(xs) and xs[i2] == id:
+        i2 += 1
+
+    j1 = 0
+    while j1 < i1:
+        while xs[j1] != ".":
+            j1 += 1
+        if not j1 < i1:
+            break
+        j2 = j1
+        while xs[j2] == ".":
+            j2 += 1
+        assert j2 <= i1
+
+        if i2 - i1 <= j2 - j1:
+            for j, i in zip(range(j1, j2), range(i1, i2)):
+                xs[j], xs[i] = xs[i], xs[j]
+            break
+        j1 = j2
+
+print(score(xs))

2024/d10.py

@@ -0,0 +1,26 @@
+from collections import deque
+from lib import Grid2D
+from lib import get_data
+
+
+data = get_data(__file__)
+g = Grid2D(data)
+
+p1 = 0
+p2 = 0
+for start in g.find("0"):
+    queue = deque([start])
+    all = set()
+    while queue:
+        node = queue.popleft()
+        if g[node] == "9":
+            all.add(node)
+            p2 += 1
+
+        for nb in g.neighbors_ort(node):
+            if int(g[node]) + 1 == int(g[nb]):
+                queue.append(nb)
+    p1 += len(all)
+
+print(p1)
+print(p2)

2024/d11.py

@@ -0,0 +1,31 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__)
+xs = ints(data)
+CACHE = {}
+
+# I had maxsize too small at first :/
+# @lru_cache(maxsize=10**12) 
+def apply(x, rest):
+    if rest == 0:
+        return 1
+
+    if (x, rest) in CACHE:
+        return CACHE[(x, rest)]
+
+    if x == 0:
+        r = apply(1, rest - 1)
+    elif len(str(x)) % 2 == 0:
+        sx = str(x)
+        a = int(sx[: len(sx) // 2])
+        b = int(sx[len(sx) // 2 :])
+        r = apply(a, rest - 1) + apply(b, rest - 1)
+    else:
+        r = apply(x * 2024, rest - 1)
+    CACHE[(x, rest)] = r
+    return r
+
+
+print(sum([apply(x, 25) for x in xs]))
+print(sum([apply(x, 75) for x in xs]))

2024/d12.py

@@ -0,0 +1,61 @@
+from lib import get_data
+from lib import Grid2D
+from collections import defaultdict
+from collections import deque
+
+data = get_data(__file__)
+
+DIRS = {
+    "N": (-1, 0),
+    "E": (0, 1),
+    "S": (1, 0),
+    "W": (0, -1),
+}.values()
+
+
+g = Grid2D(data)
+cs = defaultdict(set)
+for row in range(g.n_rows):
+    for col in range(g.n_cols):
+        c = g[(row, col)]
+        cs[c].add((row, col))
+
+t1, t2 = 0, 0
+for c, cs in cs.items():
+    while cs:
+        peri = 0
+        start = cs.pop()
+        seen = set()
+        queue = deque([start])
+        fences = set()
+        while queue:
+            pos = queue.popleft()
+            if pos in seen:
+                continue
+            seen.add(pos)
+
+            for d in DIRS:
+                nb = d[0] + pos[0], d[1] + pos[1]
+                if g.contains(nb) and g[nb] == c:
+                    queue.append(nb)
+                    cs.discard(nb)
+                else:
+                    peri += 1
+                    nb = tuple(list(nb) + [d])
+                    fences.add(nb)
+
+        nfences = set()
+        for row, col, dir in fences:
+            for dr, dc in [(1, 0), (0, 1)]:
+                nr, nc = row + dr, col + dc
+                if (nr, nc, dir) in fences:
+                    break
+            else:
+                nfences.add((row, col, dir))
+
+        c_area = len(seen)
+        t1 += c_area * peri
+        t2 += c_area * len(nfences)
+
+print(t1)
+print(t2)

2024/d13.py

@@ -0,0 +1,33 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__)
+ps = data.split("\n\n")
+
+c1, c2 = 0, 0
+for p in ps:
+    lines = p.splitlines()
+    ax, ay = ints(lines[0])
+    bx, by = ints(lines[1])
+    px, py = ints(lines[2])
+    px2 = px + 10000000000000
+    py2 = py + 10000000000000
+
+    for a in range(0, 101):
+        for b in range(0, 101):
+            if a * ax + b * bx == px and a * ay + b * by == py:
+                c1 += a * 3 + b
+
+    D = ax * by - bx * ay
+    if abs(D) > 1e-10:
+        a_ = px2 * by - bx * py2
+        b_ = ax * py2 - px2 * ay
+        if a_ % D == 0 and b_ % D == 0:
+            a = (px2 * by - bx * py2) // D
+            b = (ax * py2 - px2 * ay) // D
+
+            if a >= 0 and b >= 0:
+                c2 += a * 3 + b
+
+print(c1)
+print(c2)

2024/d14.py

@@ -0,0 +1,64 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+
+rows = 103
+cols = 101
+data = get_data(__file__)
+
+
+def score(robots):
+    quadrants = defaultdict(int)
+    for _, r, c in robots:
+        if r < rows // 2 and c < cols // 2:
+            quadrants[1] += 1
+        elif r < rows // 2 and c > cols // 2:
+            quadrants[2] += 1
+        elif r > rows // 2 and c < cols // 2:
+            quadrants[3] += 1
+        elif r > rows // 2 and c > cols // 2:
+            quadrants[4] += 1
+    t = 1
+    for q in quadrants.values():
+        t *= q
+    return t
+
+
+def print_from_xy(xs):
+    x_min = min(v[1] for v in xs)
+    x_max = max(v[1] for v in xs)
+    y_min = min(v[0] for v in xs)
+    y_max = max(v[0] for v in xs)
+    for y in range(y_min, y_max + 1):
+        row = ""
+        for x in range(x_min, x_max + 1):
+            if (x, y) in xs:
+                row += "#"
+            else:
+                row += " "
+        print(row)
+
+
+robots_speed = {}
+robots = list()
+for i, line in enumerate(data.splitlines()):
+    c, r, vc, vr = ints(line)
+    robots_speed[i] = (vr, vc)
+    robots.append((i, r, c))
+
+for j in range(rows * cols):
+    nrobots = list()
+    count = 0
+    for i, r, c in robots:
+        vr, vc = robots_speed[i]
+        nr = (r + vr) % rows
+        nc = (c + vc) % cols
+        nrobots.append((i, nr, nc))
+    robots = nrobots
+    if j == 99:
+        print(score(robots))
+    robots_coords = [(r, c) for _, r, c in robots]
+    if len(robots_coords) == len(set(robots_coords)):
+        print(j + 1)
+        # print_from_xy(robots_coords)
+        break

2024/d15.py

@@ -0,0 +1,92 @@
+from lib import get_data
+from lib import Grid2D
+
+DIRS = {
+    "^": (-1, 0),
+    ">": (0, 1),
+    "v": (1, 0),
+    "<": (0, -1),
+}
+
+data = get_data(__file__)
+data, moves = data.split("\n\n")
+
+g = Grid2D(data)
+
+
+def simulate(grid: Grid2D, moves: str):
+    (p,) = g.find("@")
+    for c in moves:
+        if c == "\n":
+            continue
+        d = DIRS[c]
+
+        to_move = set([p])
+        row = to_move
+        blocked = False
+        while True:
+            nrow = set()
+            for (
+                r,
+                c,
+            ) in row:
+                np = r + d[0], c + d[1]
+                if g[np] == "#":
+                    blocked = True
+                elif g[np] == "O":
+                    nrow.add(np)
+                elif g[np] == "[":
+                    nrow.add(np)
+                    if d == (1, 0) or d == (-1, 0):
+                        nrow.add((np[0], np[1] + 1))
+                elif g[np] == "]":
+                    if d == (1, 0) or d == (-1, 0):
+                        nrow.add((np[0], np[1] - 1))
+                    nrow.add(np)
+            to_move |= row
+            row = nrow
+            if len(row) == 0 or blocked:
+                break
+
+        if not blocked:
+            to_place = {}
+            p = p[0] + d[0], p[1] + d[1]
+
+            for tm in to_move:
+                np = tm[0] + d[0], tm[1] + d[1]
+                to_place[np] = g[tm]
+                g[tm] = "."
+
+            for pos, c in to_place.items():
+                g[pos] = c
+
+
+def score(g: Grid2D) -> int:
+    os = g.find("O")
+    if os:
+        return sum(r * 100 + c for r, c in os)
+    return sum(r * 100 + c for r, c in g.find("["))
+
+
+simulate(g, moves)
+print(score(g))
+
+ndata = ""
+for c in data:
+    if c == "#":
+        ndata += "##"
+    elif c == "O":
+        ndata += "[]"
+    elif c == ".":
+        ndata += ".."
+    elif c == "@":
+        ndata += "@."
+    else:
+        ndata += c
+
+g = Grid2D(ndata)
+(p,) = g.find("@")
+
+simulate(g, moves)
+print(score(g))
+exit()

2024/d16.py

@@ -0,0 +1,96 @@
+import heapq
+from collections import defaultdict
+from lib import get_data
+from lib import Grid2D
+
+
+data = get_data(__file__)
+
+g = Grid2D(data)
+
+
+def search(start, end, dir):
+    paths = set()
+
+    def reconstruct(parents, current):
+        seen = set()
+        to_visit = [current]
+        while to_visit:
+            current = to_visit.pop()
+            if current in seen:
+                continue
+            seen.add(current)
+            paths.add(current[0])
+            for p in parents[current]:
+                to_visit.append(p)
+
+    def dist(n1, n2):
+        """cost from node to node"""
+        if n1 == 0 or n1 == n2:
+            return 0
+        p1, d1 = n1
+        p2, d2 = n2
+        if p1 != p2:
+            return 1
+        if d1 != d2:
+            return 1000
+        assert False
+
+    def h(node):
+        """heuristic function (never overestimate)"""
+        pos = node[0]
+        return abs(pos[0] - end[0]) + abs(pos[1] - end[1])
+
+    def is_goal(node):
+        return node[0] == end
+
+    def neighbors(node):
+        pos, dir = node
+        npos = pos[0] + dir[0], pos[1] + dir[1]
+        nbs = []
+        if g.contains(npos) and g[npos] != "#":
+            nbs.append((npos, dir))
+        ndir = dir[1], -dir[0]
+        nbs.append((pos, ndir))
+        ndir = -dir[1], dir[0]
+        nbs.append((pos, ndir))
+        return nbs
+
+    starts = [(start, dir)]
+    open_set = []
+    g_score = {}
+    cost = None
+
+    for start in starts:
+        heapq.heappush(open_set, (h(start), start))
+        g_score[start] = dist(0, start)
+
+    parents = defaultdict(list)
+    while open_set:
+        current_f_score, current = heapq.heappop(open_set)
+        if is_goal(current):
+            # assert current_f_score == g_score[current]
+            gs = g_score[current]
+            if cost is None or gs <= cost:
+                cost = gs
+                reconstruct(parents, current)
+            else:
+                break
+
+        for neighbor in neighbors(current):
+            tentative_g_score = g_score[current] + dist(current, neighbor)
+            if tentative_g_score <= g_score.get(neighbor, 10**12):
+                parents[neighbor].append(current)
+                g_score[neighbor] = tentative_g_score
+                f_score = g_score[neighbor] + h(neighbor)
+                heapq.heappush(open_set, (f_score, neighbor))
+    return cost, paths
+
+
+(start,) = g.find("S")
+(end,) = g.find("E")
+dir = (0, 1)
+
+cost, paths = search(start, end, dir)
+print(cost)
+print(len(paths))

2024/d17.py

@@ -0,0 +1,61 @@
+from lib import get_data
+from lib import ints
+
+
+data = get_data(__file__)
+nums, prog = data.split("\n\n")
+regs = ints(nums)
+prog = ints(prog)
+
+i = 0
+out = []
+while i < len(prog) - 1:
+    inst, op = prog[i], prog[i + 1]
+    assert op != 7
+    combo = op if op not in [4, 5, 6] else regs[op - 4]
+    literal = op
+    match inst:
+        case 0:
+            regs[0] = regs[0] >> combo
+        case 1:
+            regs[1] = regs[1] ^ literal
+        case 2:
+            regs[1] = combo % 8
+        case 3:
+            if regs[0] != 0:
+                i = literal - 2
+        case 4:
+            regs[1] = regs[1] ^ regs[2]
+        case 5:
+            out.append(combo % 8)
+        case 6:
+            regs[1] = regs[0] // (2**combo)
+        case 7:
+            regs[2] = regs[0] // (2**combo)
+        case _:
+            assert False
+    i += 2
+
+print(",".join(map(str, out)))
+
+
+def get_a(a_current, xs):
+    if len(xs) == 0:
+        return [a_current // 8]
+    x = xs[0]
+    aan = []
+    for a_new in range(8):
+        a = a_current + a_new
+        b = a % 8
+        assert b == a_new
+        b = b ^ 1
+        c = a >> b
+        b = b ^ c
+        b = b ^ 5
+        if (b % 8) == x:
+            aan += get_a(a << 3, xs[1:])
+    return aan
+
+
+aa = get_a(0, list(reversed(prog)))
+print(min(aa))

2024/d18.py

@@ -0,0 +1,67 @@
+import heapq
+from lib import get_data
+from lib import ints
+from lib import Grid2D
+
+data = get_data(__file__)
+
+size = 71
+grid = "\n".join(["." * size for _ in range(size)])
+
+g = Grid2D(grid)
+for i, line in enumerate(data.splitlines()):
+    x, y = ints(line)
+    g[(y, x)] = "x"
+
+    start = (0, 0)
+    end = (size - 1, size - 1)
+
+    def dist(n1, n2):
+        """cost from node to node"""
+        if n1 == 0 or n1 == n2:
+            return 0
+        return 1
+
+    def h(node):
+        """heuristic function (never overestimate)"""
+        return abs(node[0] - end[0]) + abs(node[1] - end[1])
+
+    def is_goal(node):
+        return node == end
+
+    def neighbors(node):
+        nbs = []
+        for nb in g.neighbors_ort(node):
+            if g[nb] != "x":
+                nbs.append(nb)
+        return nbs
+
+    starts = [start]
+    open_set = []
+    g_score = {}
+    cost = None
+
+    for start in starts:
+        heapq.heappush(open_set, (h(start), start))
+        g_score[start] = dist(0, start)
+
+    while open_set:
+        current_f_score, current = heapq.heappop(open_set)
+        if is_goal(current):
+            assert current_f_score == g_score[current]
+            cost = g_score[current]
+            break
+
+        for neighbor in neighbors(current):
+            tentative_g_score = g_score[current] + dist(current, neighbor)
+            if neighbor not in g_score or tentative_g_score < g_score[neighbor]:
+                g_score[neighbor] = tentative_g_score
+                f_score = g_score[neighbor] + h(neighbor)
+                heapq.heappush(open_set, (f_score, neighbor))
+
+    if i == 1023:
+        print(cost)
+
+    if cost is None:
+        print(line)
+        break

2024/d19.py

@@ -0,0 +1,30 @@
+from lib import get_data
+from functools import cache
+
+data = get_data(__file__)
+lines = data.splitlines()
+patterns = set(lines[0].split(", "))
+
+
+@cache
+def valid(line):
+    if line == "":
+        return 1
+    r = 0
+    for j in range(1, len(line) + 1):
+        sub = line[:j]
+        if sub in patterns:
+            r += valid(line[j:])
+    return r
+
+
+p1, p2 = 0, 0
+lines = lines[2:]
+for line in lines:
+    v = valid(line.strip())
+    if v > 0:
+        p1 += 1
+        p2 += v
+
+print(p1)
+print(p2)

2024/d20.py

@@ -0,0 +1,90 @@
+from collections import deque
+from lib import get_data
+from lib import Grid2D
+
+
+data = """###############
+#...#...#.....#
+#.#.#.#.#.###.#
+#S#...#.#.#...#
+#######.#.#.###
+#######.#.#...#
+#######.#.###.#
+###..E#...#...#
+###.#######.###
+#...###...#...#
+#.#####.#.###.#
+#.#...#.#.#...#
+#.#.#.#.#.#.###
+#...#...#...###
+###############
+"""
+data = get_data(__file__)
+
+g = Grid2D(data)
+
+(start,) = g.find("S")
+(end,) = g.find("E")
+
+cost = 0
+sd = dict()
+de = dict()
+
+queue = deque([(start[0], start[1], 0)])
+seen = set()
+while queue:
+    r, c, cost = queue.popleft()
+
+    if (r, c) in sd:
+        continue
+    sd[(r, c)] = cost
+
+    if (r, c) == end:
+        break
+
+    for r, c in g.neighbors_ort((r, c)):
+        if g[(r, c)] != "#":
+            queue.append((r, c, cost + 1))
+
+seen = set()
+queue = deque([(end[0], end[1], 0)])
+while queue:
+    r, c, cost = queue.popleft()
+
+    if (r, c) in de:
+        continue
+    de[(r, c)] = cost
+
+    if (r, c) == start:
+        break
+
+    for r, c in g.neighbors_ort((r, c)):
+        if g[(r, c)] != "#":
+            queue.append((r, c, cost + 1))
+
+for max_steps in [2, 20]:
+    cheats = set()
+    for cr, cc in g.find("S."):
+        start = cr, cc, 0
+        seen = set()
+        queue = deque([start])
+        while queue:
+            r, c, steps = queue.popleft()
+            if steps > max_steps:
+                continue
+
+            if (r, c) in seen:
+                continue
+            seen.add((r, c))
+
+            if g[(r, c)] != "#":
+                ncost = sd[(cr, cc)] + steps + de[(r, c)]
+                if cost - ncost >= 100:
+                    cheats.add((cr, cc, r, c))
+
+            for dr, dc in [(-1, 0), (0, 1), (1, 0), (0, -1)]:
+                nr, nc = r + dr, c + dc
+                if g.contains((nr, nc)):
+                    queue.append((nr, nc, steps + 1))
+
+    print(len(cheats))

2024/d21.py

@@ -0,0 +1,87 @@
+from lib import get_data
+from collections import deque
+from functools import cache
+
+
+data = get_data(__file__)
+# data = """029A
+# 980A
+# 179A
+# 456A
+# 379A"""
+
+
+def new_dir(current, move):
+    return {
+        "<": {">": "v"},
+        "^": {">": "A", "v": "v"},
+        "v": {"<": "<", ">": ">", "^": "^"},
+        ">": {"^": "A", "<": "v"},
+        "A": {"<": "^", "v": ">"},
+    }[current].get(move, None)
+
+
+def new_num(current, move):
+    return {
+        "7": {">": "8", "v": "4", },
+        "8": {"<": "7", ">": "9", "v": "5"},
+        "9": {"<": "8", "v": "6"},
+        "4": {"^": "7", ">": "5", "v": "1"},
+        "5": {"^": "8", ">": "6", "<": "4", "v": "2"},
+        "6": {"^": "9", "<": "5", "v": "3"},
+        "1": {"^": "4", ">": "2"},
+        "2": {"^": "5", ">": "3", "<": "1", "v": "0"},
+        "3": {"^": "6", "<": "2", "v": "A"},
+        "0": {"^": "2", ">": "A"},
+        "A": {"^": "3", "<": "0"},
+    }[current].get(move, None)
+
+
+@cache
+def find(code, depth, lookup):
+    if depth == 0:
+        return len(code)
+    code = list(code)
+    t = 0
+    current = "A"
+    while code:
+        solutions = []
+        target = code.pop(0)
+        start = (current, "")
+        seen = set()
+        queue = deque([start])
+        while queue:
+            node = queue.popleft()
+            if node in seen:
+                continue
+            seen.add(node)
+            if node[0] == target:
+                solution = node[1] + "A"
+                if len(solutions) == 0:
+                    solutions.append(solution)
+                elif len(solutions[-1]) == len(solution):
+                    solutions.append(solution)
+                else:
+                    break
+                continue
+
+            for c in "<>v^":
+                next = lookup(node[0], c)
+                if next is not None:
+                    queue.append((next, node[1] + c))
+        current = target
+        t += min(find(code, depth - 1, new_dir) for code in solutions)
+    return t
+
+
+p1, p2 = 0, 0
+for line in data.splitlines():
+    i = int("".join([c for c in line if c.isdigit()]))
+    s1 = find(line, 3, new_num)
+    s2 = find(line, 26, new_num)
+    p1 += s1 * i
+    p2 += s2 * i
+
+
+print(p1)
+print(p2)

2024/d22.py

@@ -0,0 +1,56 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+
+
+data = get_data(__file__)
+
+
+def secret(x):
+    x ^= x * 64
+    x %= 16777216
+
+    x ^= x // 32
+    x %= 16777216
+
+    x ^= x * 2048
+    x %= 16777216
+    return x
+
+
+def slice(xs, n):
+    return [slice for slice in zip(*[xs[i:] for i in range(n)])]
+
+
+codes = defaultdict(int)
+
+
+def int_seq(x):
+    xs = []
+    for _ in range(2000):
+        xs.append(x % 10)
+        x = secret(x)
+    ds = [a - b for a, b in zip(xs[1:], xs)]
+
+    seen = set()
+    for s in slice(list(zip(xs[1:], ds)), 4):
+        code = tuple([e[1] for e in s])
+        v = s[-1][0]
+        if not code in seen:
+            codes[code] += v
+            seen.add(code)
+
+
+for line in data.splitlines():
+    (x,) = ints(line)
+
+s = 0
+for line in data.splitlines():
+    (x,) = ints(line)
+    int_seq(x)
+    for _ in range(2000):
+        x = secret(x)
+    s += x
+
+print(s)
+print(max(codes.values()))

2024/d23.py

@@ -0,0 +1,43 @@
+from lib import get_data
+from collections import defaultdict
+
+data = get_data(__file__)
+g = defaultdict(set)
+
+for line in data.splitlines():
+    a, b = line.split("-")
+    g[a].add(b)
+    g[b].add(a)
+
+
+cs = set()
+for a, bs in g.items():
+    for b in bs:
+        for c in g[b]:
+            if c in bs:
+                cs.add(tuple(sorted([a, b, c])))
+
+cs = [t for t in cs if any(x.startswith("t") for x in t)]
+print(len(cs))
+
+
+def find_largest_clique(graph):
+    def bron_kerbosch(r, p, x, max_clique):
+        if not p and not x:
+            if len(r) > len(max_clique[0]):
+                max_clique[0] = r.copy()
+            return
+
+        for v in p.copy():
+            neighbors = graph[v]
+            bron_kerbosch(r | {v}, p & neighbors, x & neighbors, max_clique)
+            p.remove(v)
+            x.add(v)
+
+    max_clique = [set()]
+    bron_kerbosch(set(), set(graph.keys()), set(), max_clique)
+    return max_clique[0]
+
+
+cs = find_largest_clique(g)
+print(",".join(sorted(cs)))

2024/d24.py

@@ -0,0 +1,143 @@
+from lib import get_data
+from lib import ints
+
+LHS, OP, RHS, _, OUT = 0, 1, 2, 3, 4
+
+
+def run(states, gates):
+    change = True
+    while change:
+        change = False
+        for gate in gates:
+            i1, op, i2, _, out = gate
+            if i1 in states and i2 in states and out not in states:
+                change = True
+                outv = None
+                match op:
+                    case "OR":
+                        outv = states[i1] | states[i2]
+                    case "XOR":
+                        outv = states[i1] ^ states[i2]
+                    case "AND":
+                        outv = states[i1] & states[i2]
+                assert outv is not None
+                states[out] = outv
+
+    i, t = 0, 0
+    while True:
+        si = f"z{i:02}"
+        if not si in states:
+            break
+        if states[si]:
+            t += 2**i
+        i += 1
+    return t
+
+
+data = get_data(__file__)
+
+s1, s2 = data.split("\n\n")
+states = {}
+for line in s1.splitlines():
+    gate, value = line.split(": ")
+    states[gate] = int(value)
+
+gates = []
+out_to_index = {}
+xors = {}
+zz = []
+for i, line in enumerate(s2.splitlines()):
+    o1, op, o2, _, out = line.split()
+    o1, o2 = sorted([o1, o2])
+    gate = [o1, op, o2, "->", out]
+    gates.append(gate)
+    out_to_index[out] = i
+    if out.startswith("z"):
+        zz.append(out)
+    if op == "XOR" and o1.startswith("x"):
+        (index,) = ints(o1)
+        xors[index] = gate
+
+p1 = run(states, gates)
+print(p1)
+
+NUMBER_Z_GATES = ints(sorted(zz)[-1])[0] + 1
+# print(NUMBER_Z_GATES)
+# pprint(xors)
+
+xx = [f"x{i:02}" for i in range(NUMBER_Z_GATES - 1)]
+yy = [f"y{i:02}" for i in range(NUMBER_Z_GATES - 1)]
+
+# def resolve(x):
+#     if x in xx or x in yy:
+#         return f"{x}"
+#         # return x
+#     a, op, b = gate_to_in[x]
+#     aa = resolve(a)
+#     bb = resolve(b)
+#     # print(aa, bb)
+#     aa, bb = sorted([aa, bb], reverse=True)
+#     op = "^" if op == "XOR" else ("|" if op == "OR" else "&")
+#     return f"({aa} {op} {bb})"
+#     # return [aa, op, bb]
+
+
+def find_xor(index):
+    xor = xors[index][OUT]
+    for gate in gates:
+        if gate[OP] == "XOR" and (gate[LHS] == xor or gate[RHS] == xor):
+            return gate
+    return None
+
+
+corrected = []
+for i in range(NUMBER_Z_GATES):
+    sx, sy, sz = [f"{c}{i:02}" for c in "xyz"]
+    gate = gates[out_to_index[sz]]
+    if i == 0:
+        assert gate == xors[i]
+    elif i == NUMBER_Z_GATES - 1:
+        pass  # last gate needs special check
+    else:
+        fixed = False
+        xor = xors[i]
+        if gate[OP] != "XOR":
+            cgate = find_xor(i)
+            assert cgate is not None
+            gate[OUT], cgate[OUT] = cgate[OUT], gate[OUT]
+            corrected.append(gate[OUT])
+            corrected.append(cgate[OUT])
+            out_to_index[gate[OUT]], out_to_index[cgate[OUT]] = (
+                out_to_index[cgate[OUT]],
+                out_to_index[gate[OUT]],
+            )
+            fixed = True
+            # print(f"[swap] {gate} <-> {cgate}")
+            gate = gates[out_to_index[sz]]
+        assert gate[OP] == "XOR"
+
+        # print(gate)
+        i_lhs, i_rhs = out_to_index[gate[LHS]], out_to_index[gate[RHS]]
+        a, b = gates[i_lhs], gates[i_rhs]
+
+        if a == xor:
+            # print(f"[ok] {sz} ({fixed})")
+            pass
+        elif b == xor:
+            # print(f"[ok] {sz} ({fixed})")
+            gate[0], gate[2] = gate[2], gate[0]
+        else:
+            if a[OP] == "AND":
+                a[OUT], xor[OUT] = xor[OUT], a[OUT]
+                corrected.append(a[OUT])
+                corrected.append(xor[OUT])
+                # print(f"[swap] {a} <-> {xor}")
+                out_to_index[a[OUT]], out_to_index[xor[OUT]] = (
+                    out_to_index[xor[OUT]],
+                    out_to_index[a[OUT]],
+                )
+                # print(f"[ok] {sz} (manual fix)")
+            else:
+                print(f"[nok] {sz} (don't know how to fix)")
+
+print(",".join(sorted(corrected)))

2024/d25.py

@@ -0,0 +1,25 @@
+from lib import get_data
+from lib import Grid2D
+
+data = get_data(__file__)
+
+locks = []
+keys = []
+
+for o in data.split("\n\n"):
+    g = Grid2D(o)
+    if all(g[(0, c)] == "#" for c in range(g.n_cols)):
+        keys.append(g)
+    elif all(g[g.n_rows - 1, c] == "#" for c in range(g.n_cols)):
+        locks.append(g)
+    else:
+        assert False
+
+t = 0
+for key in keys:
+    for lock in locks:
+        k = key.find("#")
+        l = lock.find("#")
+        if len(k) + len(l) == len(set(k) | set(l)):
+            t += 1
+print(t)

2024/lib.py

@@ -0,0 +1 @@
+../lib.py

2025/d01.py

@@ -0,0 +1,22 @@
+from lib import get_data
+
+NUM = 100
+
+data = get_data(__file__)
+
+pos = 50
+r1, r2 = 0, 0
+for line in data.splitlines():
+    d = line[0]
+    n = int(line[1:])
+    dir = 1 if d == "R" else -1
+
+    for _ in range(n):
+        pos = (pos + dir) % NUM
+        if pos == 0:
+            r2 += 1
+    if pos == 0:
+        r1 += 1
+
+print(r1)
+print(r2)

2025/d02.py

@@ -0,0 +1,34 @@
+from lib import get_data
+
+
+data = get_data(__file__)
+
+def is_invalid(xs: str) -> bool:
+    for seq_len in range(1, len(xs) // 2 + 1):
+        if xs[:seq_len] == xs[seq_len:]:
+            return True
+    return False
+
+def is_invalid2(xs: str) -> bool:
+    for seq_len in range(1, len(xs)):
+        if len(xs) % seq_len != 0:
+            continue
+        for repeat in range(len(xs) // seq_len):
+            i = seq_len * repeat
+            if xs[:seq_len] != xs[i:i + seq_len]:
+                break
+        else:
+            return True
+    return False
+
+r1, r2 = 0, 0
+for id_range in data.split(","):
+    lo, up = list(map(int, id_range.split("-")))
+    for id in range(lo, up + 1):
+        if is_invalid(str(id)):
+            r1 += id
+        if is_invalid2(str(id)):
+            r2 += id
+
+print(r1)
+print(r2)

2025/d03.py

@@ -0,0 +1,34 @@
+from lib import get_data
+
+data = get_data(__file__)
+
+
+def max_joltage(xs: str, target_len: int) -> int:
+    def dynamic(xs: str) -> dict[int, str]:
+        if len(xs) == 0:
+            return {0: ""}
+
+        rs = dynamic(xs[1:])
+        for i in range(target_len, 0, -1):
+            if not (i - 1) in rs:
+                continue
+            nv = int(xs[0] + rs[i - 1])
+            if not i in rs:
+                rs[i] = str(nv)
+            elif nv > int(rs[i]):
+                rs[i] = str(nv)
+        return rs
+
+    rs = dynamic(xs)
+    return int(rs[target_len])
+
+
+r1 = 0
+r2 = 0
+for line in data.splitlines():
+    r1 += max_joltage(line, 2)
+    r2 += max_joltage(line, 12)
+
+
+print(r1)
+print(r2)

2025/d04.py

@@ -0,0 +1,32 @@
+from lib import get_data, Grid2D
+
+data = get_data(__file__)
+g = Grid2D(data)
+
+r = 0
+adjs = []
+for pos in g.all_coords():
+    if g[pos] != "@":
+        continue
+    nr_of_rolls_adj = len([nb for nb in g.neighbors_adj(pos) if g[nb] == "@"])
+    if nr_of_rolls_adj < 4:
+        r += 1
+        adjs.append(pos)
+print(r)
+
+r = 0
+while True:
+    adjs = []
+    for pos in g.all_coords():
+        if g[pos] != "@":
+            continue
+        nr_of_rolls_adj = len([nb for nb in g.neighbors_adj(pos) if g[nb] == "@"])
+        if nr_of_rolls_adj < 4:
+            adjs.append(pos)
+    if adjs:
+        r += len(adjs)
+        for a in adjs:
+            g[a] = "."
+    else:
+        break
+print(r)

2025/d05.py

@@ -0,0 +1,45 @@
+from lib import get_data
+
+data = get_data(__file__)
+
+ranges, ids = data.split("\n\n")
+ids = tuple(map(int, ids.splitlines()))
+ranges = [list(map(int, line.split("-"))) for line in ranges.splitlines()]
+
+updated = True
+while updated:
+    updated = False
+    sorted_ranges = []
+    for lo, up in ranges:
+        assert lo <= up
+        for i in range(len(sorted_ranges)):
+            slo, sup = sorted_ranges[i]
+            if up + 1 < slo:
+                sorted_ranges.insert(i, (lo, up))
+            elif lo < slo:
+                sorted_ranges[i] = (lo, max(up, sup))
+                updated = True
+            elif lo <= sup:
+                sorted_ranges[i] = (slo, max(up, sup))
+                updated = True
+            else:
+                continue
+            break
+        else:
+            sorted_ranges.append((lo, up))
+    ranges = sorted_ranges
+
+
+result_part_1 = 0
+for id_to_check in ids:
+    for lo, up in ranges:
+        if lo <= id_to_check <= up:
+            result_part_1 += 1
+            break
+print(result_part_1)
+
+result_part_2 = 0
+for lo, up in ranges:
+    result_part_2 += up - lo + 1
+print(result_part_2)
+assert result_part_2 == 350780324308385

2025/d06.py

@@ -0,0 +1,60 @@
+from lib import get_data
+from typing import TypeVar
+
+T = TypeVar('T')
+
+data = """123 328  51 64 
+ 45 64  387 23 
+  6 98  215 314
+*   +   *   +  """
+data = get_data(__file__)
+
+def mul(xs):
+    r = 1
+    for x in xs:
+        r *= x
+    return r
+
+lines = zip(*[line.split() for line in data.splitlines()])
+
+r = 0
+for xs in lines:
+    xs, op = xs[:-1], xs[-1]
+    xs = list(map(int, xs))
+    if op == "+":
+        r += sum(xs)
+    elif op == "*":
+        r += mul(xs)
+    else:
+        assert False, "Unexpected op"
+print(r)
+
+def split(xs: list[T], delim: T) -> list[list[T]]:
+    res = [[]]
+    for x in xs:
+        if x == delim:
+            res.append([])
+        else:
+            res[-1].append(x)
+    return res
+
+chars_trans: list[tuple[str]]  = list(zip(*[line for line in data.splitlines()]))
+lines_trans: list[str] = list(map(lambda line: "".join(line).strip(), chars_trans))
+cols: list[list[str]] = split(lines_trans, '')
+
+r2 = 0
+for xs in cols:
+    x0 = xs[0]
+    acc, op = int(x0[:-1]), x0[-1]
+    for x in xs[1:]:
+        x = int(x)
+        if op == "+":
+            acc += x
+        elif op == "*":
+            acc *= x
+        else:
+            assert False, "Unexpected op"
+    r2 += acc
+
+print(r2)
+

2025/d07.py

@@ -0,0 +1,59 @@
+from lib import get_data, Grid2D
+from collections import defaultdict
+
+
+data = """.......S.......
+...............
+.......^.......
+...............
+......^.^......
+...............
+.....^.^.^.....
+...............
+....^.^...^....
+...............
+...^.^...^.^...
+...............
+..^...^.....^..
+...............
+.^.^.^.^.^...^.
+..............."""
+data = get_data(__file__)
+
+g = Grid2D(data)
+beams = [g.find('S')[0][1]]
+
+splits = 0
+for row in range(1, g.n_rows - 1):
+    new_beams = set()
+    for beam in beams:
+        field = g[(row, beam)]
+        if field == "^":
+            splits += 1
+            new_beams.add(beam - 1)
+            new_beams.add(beam + 1)
+        elif field == ".":
+            new_beams.add(beam)
+        else:
+            assert False, "unexpected field"
+    beams = list(new_beams)
+    # print(beams)
+
+print(splits)
+
+beams = {g.find('S')[0][1]: 1}
+for row in range(1, g.n_rows - 1):
+    new_beams = defaultdict(int)
+    for beam, count in beams.items():
+        field = g[(row, beam)]
+        if field == "^":
+            new_beams[beam - 1] += count
+            new_beams[beam + 1] += count
+        elif field == ".":
+            new_beams[beam] += count
+        else:
+            assert False, "unexpected field"
+    beams = new_beams
+
+print(sum(beams.values()))
+

2025/lib.py

@@ -0,0 +1 @@
+../lib.py

README.md

@@ -2,211 +2,60 @@
 
 Solutions and utility script for Advent of Code challenges in Python.
 
-## AoC 2015
+## AoC 2025
 
-- Day 1: 3:10
+Only twelve problems and no leaderboard this year. That means life will be less
-- Day 2: 5:24 :/ 
+stressful and this will actually be more fun. Thank you Eric Wastl and let's go!
-- Day 3: 7:26 ... :/
-- Day 4: 5:11 ...
-- Day 5: 14:05 o.O
-- Day 6: 15:00
-- Day 7: 17:00
-- Day 8: 14:55
-- Day 9: 13:48
-- Day 10: 70:00 ... slow, but fun
-- Day 11: 12:30
-- Day 12: 6:03
-- Day 13: 7:06 (would have been first by a minute, probably 70ish in 2023)
-- Day 14: 27:45 ... that was weak, logic error for part 2 :/
-- Day 15: 16:00 I should probably stop brute forcing these optimization problems
-- Day 16: 19:00
-- Day 17: 9:05
-- Day 18: 10:39
-- Day 19: Many days... yeah this one took me way too long to figure out
-- Day 20: 10:54
-- Day 21: 25:52 cute bug where I didn't consider that no armor is an option
-- Day 22: That was bad. Did not know how to choose between dfs/bfs and logic errors.
-- Day 23: 10:00
-- Day 24: 20:00 ugly - recursive solution would be more elegant
-- Day 25: 9:34
 
-## AoC 2016
+- Day 1: Maybe the hardest day 1 part 2 ever for me? I struggled to calculate
+  the number of ticks on 0 directly and ended up just iterating over all the
+  ticks naively. Maybe I should revisit this.
+- Day 2: The simple direct approach with iterating over all the IDs in the
+  ranges just worked okay. Not pretty but acceptable.
+- Day 3: Fun dynamic programming problem. Part 2 took me a little too long
+  overall but it was fun.
+- Day 4: One of the easier grid based puzzles. Less than five minutes with
+  existing grid library.
+- Day 5: A problem with ranges; I decided to implement proper range merging this
+  time because I always kind of avoid that. I could probably decrease the
+  complexity from O(n^2) to O(n log(n)) but I am happy that I've implemented
+  merging at all.
+- Day 6: Transposing some rows and cols. Fun and good to keep the brain fit
+  but not really hard. I would have been way too slow for the leaderboard
+  in pre-AI years.
+- Day 7: Grid puzzle that required non-naiv implementation for part 2. Took
+  me a second to realize that I could not save the coordinates by list but
+  had to use a count to be efficient.
+- Day 8:
 
-- Day 1: 29:00 That was emberassingly slow. Out of my rhythm?
-- Day 2: 13:24 Getting back into it but still slow af, obviously.
-- Day 3: 11:20 Ugly and slow.
-- Day 4: 21:05 -__-
-- Day 5: 29:35 -___-
-- Day 6: 4:20 okay
-- Day 7: 31:20 hmm
-- Day 8: 14:50 meh
-- Day 9: 26:00 okay
-- Day 10: 23:07 okay
-- Day 11: 75:00 -__-
-- Day 12: 10:05 okay
-- Day 13: 9:43 okayish
-- Day 14: 120:00 struggled with this one (example incorrect?)
-- Day 15: Trial and error. Should use CRT instead.
-- Day 16: 14:11
-- Day 17: 45:00 didn't follow instructions... focus!
-- Day 18: 9:43
-- Day 19: 90:00 that wasn't easy for me
-- Day 20: 67:00
-- Day 21: 32:33
-- Day 22: 90:00
-- Day 23: 60:00
-- Day 24: 48:00
-- Day 25: 6:45
 
-## AoC 2017
+## AoC 2024
 
-- Day 1: 7:30
+- Day  1: `00:01:30   124      0   00:02:49    141      0`
-- Day 2: 6:15
+- Day  2: `00:05:34   686      0   00:08:21    531      0`
-- Day 3: 75:00 hmm should have been way quicker
+- Day  3: `00:01:48   165      0   00:02:40     56     45`
-- Day 4: 3:02
+- Day  4: `00:07:47  1101      0   00:24:07   2410      0`
-- Day 5: 6:13
+- Day  5: `00:07:07   679      0   00:23:02   1998      0`
-- Day 6: 8:37
+- Day  6: `00:09:43  1082      0   00:16:29    464      0`
-- Day 7: 19:22
+- Day  7: `00:12:29  2058      0   00:13:08   1170      0`
-- Day 8: 8:15
+- Day  8: `00:15:59  1742      0   00:26:56   2190      0`
-- Day 9: 6:10
+- Day  9: `00:48:23  6055      0   01:09:38   3159      0`
-- Day 10: 55:00
+- Day 10: `00:19:47  2976      0   00:20:47   2244      0`
-- Day 11: 66:06
+- Day 11: `00:05:13   642      0   00:33:07   2673      0`
-- Day 12: 6:44
+- Day 12: `00:30:30  3540      0   11:41:33  16212      0`
-- Day 13: 120:00
+- Day 13: `00:05:35   225      0   00:55:48   2544      0`
-- Day 14: 17:48
+- Day 14: `00:20:41  2136      0   00:35:14   1048      0`
-- Day 15: 11:40
+- Day 15: `   >24h  32248      0       >24h  23671      0`
-- Day 16: 13:16
+- Day 16: `   >24h  24941      0       >24h  20575      0`
-- Day 17: 55:00
+- Day 17: `17:34:16 23722      0       >24h  17778      0`
-- Day 18: 23:00
+- Day 18: `14:35:01 20398      0   14:37:18  19550      0`
-- Day 19: 45:00
+- Day 19: `00:14:37  2001      0   00:19:43   1584      0`
-- Day 20: 9:55 (would have been 10th)
+- Day 20: `01:08:53  3637      0   01:53:01   2837      0`
-- Day 21: 90:00
+- Day 21: `00:48:40   215      0       >24h  16427      0`
-- Day 22: 25:00
+- Day 22: `00:13:04  1930      0   00:28:29    739      0`
-- Day 23: Multiple days... but super fun.
+- Day 23: `   >24h  20096      0       >24h  17620      0`
-- Day 24: 15:45 (48th)
+- Day 24: `15:57:01 17307      0       >24h  11326      0`
-- Day 25: 41:00
+- Day 25: `10:41:54 14140      0       >24h  13631      0`
-
-## AoC 2018
-
-- Day 1: 1:49 (2nd)
-- Day 2: 10:53
-- Day 3: 6:16 (24th)
-- Day 4: 25:16
-- Day 5: 17:03
-- Day 6: 1:10:29
-- Day 7: 20:15
-- Day 8: 18:35
-- Day 9: 1:17:52
-- Day 10: 19:14
-- Day 11: 22:52
-- Day 12: 180:00
-- Day 13: 73:09
-- Day 14: 20:48
-- Day 15: 185:11
-- Day 16: 36:10
-- Day 17: 180:00
-- Day 18: 24:04
-- Day 19: days, super fun, but hard for me
-- Day 20:
-- Day 21: 28:40 (16th - brute force but still not so bad)
-- Day 22: 185:00 (should not have been so slow but was fun)
-- Day 23:
-
-## AoC 2019
-
-- Day 1: 4:25   (copy and paste error, no leaderboard)
-- Day 2: 7:07   (19th)
-- Day 3: 10:46  (37th)
-- Day 4: 8:48   (just too slow, no leaderboard)
-- Day 5: 34:24  (that wasn't hard at all)
-- Day 6: 23:17  (so slow, no leaderboard)
-- Day 7: 72:17  (I found that one challenging, 30:33 would have been required for leaderboard)
-- Day 8: 08:55  (54th)
-- Day 9: 115:00 (Try to read next time.)
-- Day 10: 76:00 (This wasn't easy for me. Fun, though.)
-- Day 11: 21:04 (Too slow, but fun.)
-- Day 12: days  (Took me a while to get the right idea.)
-- Day 13: >120:00 (Just struggling so much for some reason.)
-- Day 14: >120:00 (Hmm, wasn't that hard either.)
-- Day 15: >120:00 (I am really weak at the moment.)
-- Day 16: days    (Wow. Just too hard for me to solve quickly?)
-- Day 17: days    (Fun but too tricky for me to be fast.)
-- Day 18: days    (Slow and slow algorithm.)
-- Day 19: 40:00   (Way too slow! Oversight error. Come on.)
-- Day 20: days    (Not actually that hard but I struggled for no reason.) 
-- Day 21: days    (But it was super fun!)
-- Day 22:
-
-## AoC 2020
-
-- Day 1: 2:48   (people weren't able to submit because of a website outage)
-- Day 2: 4:47   (no leaderboard, you can tell it's getting faster)
-- Day 3: 7:06   (way too slow, lol; time to take it seriously)
-- Day 4: 14:30  (yo, I am just too slow)
-- Day 5: 11:53  (not competitive)
-- Day 6: 4:11   (75th, finally on the leaderboard)
-- Day 7: 24:39  (bad)
-- Day 8: 6:26   (43th, tied George Hotz :)
-- Day 9: 7:37   (choked bad)
-- Day 10: 34:27 (so weak)
-- Day 11: 21:05 (hmmm, I rally have to analyze why I am so slow)
-- Day 12: 21:52 (just slow again for an easy problem)
-- Day 13: 18:00 (I don't really understand the CRT to be honest)
-- Day 14: 40:26 (Made a bunch of mistakes even misunderstanding Python)
-- Day 15: 17:57 (Too slow for an easy one like this)
-- Day 16: 33:00 (Not too unhappy really.)
-- Day 17: 10:00 (40th)
-- Day 18: 80:00 (I am struggling with stuff where parsing is involved)
-- Day 19: 78:00 (Should have been faster)
-- Day 20: 95:00 (Lot's of code)
-- Day 21: 23:02 (Simply to slow)
-- Day 22: 45:49 (Simple and too slow)
-- Day 23: 105:00 (Sad)
-- Day 24: 15:38 (Close to leaderboard)
-- Day 25: 14:40 (Way too slow)
-
-## AoC 2022
-
-Done with this. Overall everything is solvable. It's more about consistency
-and focus. Of course, learning more algorithms and techniques helps.
-
-**Times:**
-
-- Day  1: 7:52 ... so slow brah :/ top 100 required 2:05...
-- Day  2: 22:30 ... I mistyped the first and second was just bad top 100 would
-  have been 6:16 (doable?)
-- Day  3: 13:08 actually decent but top 100 required 5:24
-- Day  4: 7:08 but top 100 required 3:33 still okay
-- Day  5: 11:56 but 7:58 for top 100... getting better?
-- Day  6: 3:50 but 2:25 for leaderboard :D
-- Day  7: 27:55 and 14:47 for leaderboard; okay, I would say
-- Day  8: 61:00 and 10:00 for leaderboard; I need template code for searching
-  coordinate systems
-- Day  9: 58:00 and 7:32 for leaderboard; I need code for 2D stuff
-- Day 10: 25:20 and 12:17 for leaderboard; okay, okay
-- Day 11: 45:00 and 18:00 for leaderboard; arg, it was doable man
-- Day 12: 39:45 and 9:46 for leaderboard; the people are ready for their
-  searches :D
-- Day 13: 44:00 and 12:56 for leaderboard; these people are just good,
-  seriously
-- Day 14: 35:00 and 14:54; I just have to get that much quicker... 2D code!
-- Day 15: 150:00 and 27:00; I didn't use Manhattan dist initially, lot's of
-  debugging
-- Day 16: 52:00 and 64:00; ARE YOU SAYING I WOULD HAVE MADE THE
-  LEADERBOARD?!?!?!?!?!?!?!
-- Day 17: Second one was fun with having to detect the repetition.
-- Day 18: 12:00 and 32:00; really straightforward and of course way too slow.
-- Day 19: Slow. (2024-09-13 improved with help from hyper neutrino.)
-- Day 20: Struggled way too much.
-- Day 21: Straightforward and relatively fast.
-- Day 22: Very hard and wasn't able to do hands free. Even the best guys took
-  over an hour.
-- Day 23: Super straightforward, but took me way longer than it should have
-  because I loose focus and make silly errors. Like back in Middleschool.
-- Day 24: Easy. Should have been faster, but no crazy mistakes. Still way too
-  slow for something easy like this.
-- Day 25: Quickly solved via constraint solver. Actual solution much simpler. Don't know
-  if I would have been able to figure it out.
 
 
 ## AoC 2023
@@ -255,3 +104,250 @@ and focus. Of course, learning more algorithms and techniques helps.
   nodes. I should probably try to write an algorith that does that, but meh.
   Manually plotting requires matplotlib and networkx packages.
 
+
+## AoC 2022
+
+Done with this. Overall everything is solvable. It's more about consistency
+and focus. Of course, learning more algorithms and techniques helps.
+
+**Times:**
+
+- Day  1: 7:52 ... so slow brah :/ top 100 required 2:05...
+- Day  2: 22:30 ... I mistyped the first and second was just bad top 100 would
+  have been 6:16 (doable?)
+- Day  3: 13:08 actually decent but top 100 required 5:24
+- Day  4: 7:08 but top 100 required 3:33 still okay
+- Day  5: 11:56 but 7:58 for top 100... getting better?
+- Day  6: 3:50 but 2:25 for leaderboard :D
+- Day  7: 27:55 and 14:47 for leaderboard; okay, I would say
+- Day  8: 61:00 and 10:00 for leaderboard; I need template code for searching
+  coordinate systems
+- Day  9: 58:00 and 7:32 for leaderboard; I need code for 2D stuff
+- Day 10: 25:20 and 12:17 for leaderboard; okay, okay
+- Day 11: 45:00 and 18:00 for leaderboard; arg, it was doable man
+- Day 12: 39:45 and 9:46 for leaderboard; the people are ready for their
+  searches :D
+- Day 13: 44:00 and 12:56 for leaderboard; these people are just good,
+  seriously
+- Day 14: 35:00 and 14:54; I just have to get that much quicker... 2D code!
+- Day 15: 150:00 and 27:00; I didn't use Manhattan dist initially, lot's of
+  debugging
+- Day 16: 52:00 and 64:00; ARE YOU SAYING I WOULD HAVE MADE THE
+  LEADERBOARD?!?!?!?!?!?!?!
+- Day 17: Second one was fun with having to detect the repetition.
+- Day 18: 12:00 and 32:00; really straightforward and of course way too slow.
+- Day 19: Slow. (2024-09-13 improved with help from hyper neutrino.)
+- Day 20: Struggled way too much.
+- Day 21: Straightforward and relatively fast.
+- Day 22: Very hard and wasn't able to do hands free. Even the best guys took
+  over an hour.
+- Day 23: Super straightforward, but took me way longer than it should have
+  because I loose focus and make silly errors. Like back in Middleschool.
+- Day 24: Easy. Should have been faster, but no crazy mistakes. Still way too
+  slow for something easy like this.
+- Day 25: Quickly solved via constraint solver. Actual solution much simpler. Don't know
+  if I would have been able to figure it out.
+
+
+## AoC 2021
+
+- Day  1:   4:01   (Haha. Why am I so bad?!?!)
+- Day  2:   6:36   (Okay. I might as well stop doing these.)
+- Day  3:  23:46   (How long can I take when I try to take long?)
+- Day  4:  22:18   (No way. Such stupid bugs.)
+- Day  5:  13:30   (Decent, but obviously too slow.)
+- Day  6:  16:33   (Right idea quickly but then struggled to implement.)
+- Day  7:   6:12   (Decent, but too slow again, obviously. Maybe fast enough for part 1.)
+- Day  8:  72:00   (Yeah, that was too much of a struggle.)
+- Day  9:   8:07   (37th okay, okay)
+- Day 10:  15:50   (I was pretty happy with that but double the 100th place.)
+- Day 11:  11:43   (Could have been much faster here.)
+- Day 12:  19:11   (Okayish, but of course too slow for leaderboard.)
+- Day 13:  16:48   (Should have been way faster.)
+- Day 14:  25:52   (Not hard but just too slow.)
+- Day 15:  19:17   (Not that bad. Multiplying the thing threw me off.)
+- Day 16:  50:01   (Way too slow. Was non-trivial but fun. Much better was feasible.)
+- Day 17:  21:59   (Not tricky again but struggling for no reason.)
+- Day 18: 162:00   (I couldn't figure out how to solve it as a tree so I did the basic way.)
+- Day 19:   days   (Super hard for me but super fun ultimately once I had the right approach.)
+- Day 20: 105:00   (That wasn't easy but was able to solve in one go.)
+- Day 21:  37:45   (Wasn't hard but I was just too slow.)
+- Day 22: 142:00   (Wonderful problem and hard for me but learned something new for sure.)
+- Day 23:  81:38   (Fun but obviously not competitive.)
+- Day 24: 232:00   (Super hard for me but I am proud of it.)
+- Day 25:  15:43   (That could have been much much faster.)
+
+
+## AoC 2020
+
+- Day 1: 2:48   (people weren't able to submit because of a website outage)
+- Day 2: 4:47   (no leaderboard, you can tell it's getting faster)
+- Day 3: 7:06   (way too slow, lol; time to take it seriously)
+- Day 4: 14:30  (yo, I am just too slow)
+- Day 5: 11:53  (not competitive)
+- Day 6: 4:11   (75th, finally on the leaderboard)
+- Day 7: 24:39  (bad)
+- Day 8: 6:26   (43th, tied George Hotz :)
+- Day 9: 7:37   (choked bad)
+- Day 10: 34:27 (so weak)
+- Day 11: 21:05 (hmmm, I rally have to analyze why I am so slow)
+- Day 12: 21:52 (just slow again for an easy problem)
+- Day 13: 18:00 (I don't really understand the CRT to be honest)
+- Day 14: 40:26 (Made a bunch of mistakes even misunderstanding Python)
+- Day 15: 17:57 (Too slow for an easy one like this)
+- Day 16: 33:00 (Not too unhappy really.)
+- Day 17: 10:00 (40th)
+- Day 18: 80:00 (I am struggling with stuff where parsing is involved)
+- Day 19: 78:00 (Should have been faster)
+- Day 20: 95:00 (Lot's of code)
+- Day 21: 23:02 (Simply to slow)
+- Day 22: 45:49 (Simple and too slow)
+- Day 23: 105:00 (Sad)
+- Day 24: 15:38 (Close to leaderboard)
+- Day 25: 14:40 (Way too slow)
+
+
+## AoC 2019
+
+- Day 1: 4:25   (copy and paste error, no leaderboard)
+- Day 2: 7:07   (19th)
+- Day 3: 10:46  (37th)
+- Day 4: 8:48   (just too slow, no leaderboard)
+- Day 5: 34:24  (that wasn't hard at all)
+- Day 6: 23:17  (so slow, no leaderboard)
+- Day 7: 72:17  (I found that one challenging, 30:33 would have been required for leaderboard)
+- Day 8: 08:55  (54th)
+- Day 9: 115:00 (Try to read next time.)
+- Day 10: 76:00 (This wasn't easy for me. Fun, though.)
+- Day 11: 21:04 (Too slow, but fun.)
+- Day 12: days  (Took me a while to get the right idea.)
+- Day 13: >120:00 (Just struggling so much for some reason.)
+- Day 14: >120:00 (Hmm, wasn't that hard either.)
+- Day 15: >120:00 (I am really weak at the moment.)
+- Day 16: days    (Wow. Just too hard for me to solve quickly?)
+- Day 17: days    (Fun but too tricky for me to be fast.)
+- Day 18: days    (Slow and slow algorithm.)
+- Day 19: 40:00   (Way too slow! Oversight error. Come on.)
+- Day 20: days    (Not actually that hard but I struggled for no reason.) 
+- Day 21: days    (But it was super fun!)
+- Day 22: days    (Needed some help...)
+- Day 23: 23:13   (Still too slow even though my int computer was in good shape...)
+- Day 24: 53:00   (Can I ever even get points at all?)
+- Day 25: 70:00   (Well, done at least. Super super fun!)
+
+
+## AoC 2018
+
+- Day 1: 1:49 (2nd)
+- Day 2: 10:53
+- Day 3: 6:16 (24th)
+- Day 4: 25:16
+- Day 5: 17:03
+- Day 6: 1:10:29
+- Day 7: 20:15
+- Day 8: 18:35
+- Day 9: 1:17:52
+- Day 10: 19:14
+- Day 11: 22:52
+- Day 12: 180:00
+- Day 13: 73:09
+- Day 14: 20:48
+- Day 15: 185:11
+- Day 16: 36:10
+- Day 17: 180:00
+- Day 18: 24:04
+- Day 19: days (super fun, but hard for me)
+- Day 20: weeks (a cache was all it took - weak)
+- Day 21: 28:40 (16th - brute force but still not so bad)
+- Day 22: 185:00 (should not have been so slow but was fun)
+- Day 23: days
+- Day 24: days
+- Day 25: 29:20 (slow)
+
+
+## AoC 2017
+
+- Day 1: 7:30
+- Day 2: 6:15
+- Day 3: 75:00 hmm should have been way quicker
+- Day 4: 3:02
+- Day 5: 6:13
+- Day 6: 8:37
+- Day 7: 19:22
+- Day 8: 8:15
+- Day 9: 6:10
+- Day 10: 55:00
+- Day 11: 66:06
+- Day 12: 6:44
+- Day 13: 120:00
+- Day 14: 17:48
+- Day 15: 11:40
+- Day 16: 13:16
+- Day 17: 55:00
+- Day 18: 23:00
+- Day 19: 45:00
+- Day 20: 9:55 (would have been 10th)
+- Day 21: 90:00
+- Day 22: 25:00
+- Day 23: Multiple days... but super fun.
+- Day 24: 15:45 (48th)
+- Day 25: 41:00
+
+
+## AoC 2016
+
+- Day 1: 29:00 That was emberassingly slow. Out of my rhythm?
+- Day 2: 13:24 Getting back into it but still slow af, obviously.
+- Day 3: 11:20 Ugly and slow.
+- Day 4: 21:05 -__-
+- Day 5: 29:35 -___-
+- Day 6: 4:20 okay
+- Day 7: 31:20 hmm
+- Day 8: 14:50 meh
+- Day 9: 26:00 okay
+- Day 10: 23:07 okay
+- Day 11: 75:00 -__-
+- Day 12: 10:05 okay
+- Day 13: 9:43 okayish
+- Day 14: 120:00 struggled with this one (example incorrect?)
+- Day 15: Trial and error. Should use CRT instead.
+- Day 16: 14:11
+- Day 17: 45:00 didn't follow instructions... focus!
+- Day 18: 9:43
+- Day 19: 90:00 that wasn't easy for me
+- Day 20: 67:00
+- Day 21: 32:33
+- Day 22: 90:00
+- Day 23: 60:00
+- Day 24: 48:00
+- Day 25: 6:45
+
+
+## AoC 2015
+
+- Day 1: 3:10
+- Day 2: 5:24 :/ 
+- Day 3: 7:26 ... :/
+- Day 4: 5:11 ...
+- Day 5: 14:05 o.O
+- Day 6: 15:00
+- Day 7: 17:00
+- Day 8: 14:55
+- Day 9: 13:48
+- Day 10: 70:00 ... slow, but fun
+- Day 11: 12:30
+- Day 12: 6:03
+- Day 13: 7:06 (would have been first by a minute, probably 70ish in 2023)
+- Day 14: 27:45 ... that was weak, logic error for part 2 :/
+- Day 15: 16:00 I should probably stop brute forcing these optimization problems
+- Day 16: 19:00
+- Day 17: 9:05
+- Day 18: 10:39
+- Day 19: Many days... yeah this one took me way too long to figure out
+- Day 20: 10:54
+- Day 21: 25:52 cute bug where I didn't consider that no armor is an option
+- Day 22: That was bad. Did not know how to choose between dfs/bfs and logic errors.
+- Day 23: 10:00
+- Day 24: 20:00 ugly - recursive solution would be more elegant
+- Day 25: 9:34
+

lib.py

@@ -59,6 +59,10 @@ class Grid2D:
     def hash(self):
         return tuple(map(lambda row: tuple(row), self.grid))
 
+    def clone(self):
+        from copy import deepcopy
+        return deepcopy(self)
+
     def clone_with_val(self, val):
         c = Grid2D("d\nd")
         c.n_rows = self.n_rows
@@ -226,7 +230,7 @@ def count_trailing_repeats(lst):
 class A_Star(object):
     def __init__(self, starts, is_goal, h, d, neighbors):
         """
-        :param h: heuristic function
+        :param h: heuristic function (never overestimate)
         :param d: cost from node to node function
         :param neighbors: neighbors function
         """
@@ -272,7 +276,7 @@ def extract_year_and_date(scriptname) -> tuple[str, str]:
 def get_data(filename):
     path, file = os.path.split(filename)
     year = path[-4:]
-    day = file.replace("d", "").replace(".py", "")
+    day = file.replace("d0", "").replace("d", "").replace(".py", "")
     txt_file = f"d{day}.txt"
 
     if os.path.isfile(txt_file):
@@ -297,6 +301,35 @@ def mod_inverse(a, m):
 
     g, x, _ = egcd(a, m)
     if g != 1:
-        raise Exception('Modular inverse does not exist')
+        raise Exception("Modular inverse does not exist")
     else:
         return x % m
+
+
+class V:
+    def __init__(self, *args):
+        self.xs: tuple[int] = tuple(args)
+
+    def __eq__(self, other):
+        if isinstance(other, V):
+            return all(v1 == v2 for v1, v2 in zip(self.xs, other.xs))
+        elif hasattr(other, "__len__") and len(self.xs) == len(other):
+            return all(v1 == v2 for v1, v2 in zip(self.xs, other))
+        return False
+
+    def __getitem__(self, i: int):
+        return self.xs[i]
+
+    def __hash__(self):
+        return hash(self.xs)
+
+    def __add__(self, other):
+        if isinstance(other, V):
+            return V(*[v1 + v2 for v1, v2 in zip(self.xs, other.xs)])
+        assert hasattr(other, "__len__"), f"V.__add__({self}, {other}) missing `len`"
+        assert len(self.xs) == len(other), f"V.__add__({self}, {other}) `len` mismatch"
+        return V(*[v1 + v2 for v1, v2 in zip(self.xs, other)])
+
+    def __repr__(self):
+        s = ", ".join(map(str, self.xs))
+        return f"V({s})"

pyproject.toml

@@ -0,0 +1,10 @@
+[project]
+name = "aocpy"
+version = "0.1.0"
+description = "Make ruff and ty available via uv"
+readme = "README.md"
+requires-python = ">=3.13"
+dependencies = [
+    "ruff>=0.14.11",
+    "ty>=0.0.11",
+]